President Barack Obama officially nominated former Nebraska Senator Chuck Hagel as the next U.S. secretary of defense on Monday. Obama, who is well aware of uphill confirmation battle that lies ahead due to Hagel's controversial views on Israel and other issues, called on the U.S. Senate to approve the nomination without delay.

"As I saw during our visits together to Afghanistan and Iraq, in Chuck Hagel our troops see a decorated combat veteran of character and strength. They see one of their own," Obama said on Monday as he announced Hagel's nomination.

The selection of Hagel is causing jitters in Israel, where some circles view the former Nebraska senator as unsympathetic or even hostile.

Hagel's positions on Israel's two most pressing foreign policy issues — Iran's nuclear program and relations with the Palestinians — appear to be at odds with the Israeli government's stance, and critics fear the appointment could increase pressure on Israel to make unwanted concessions. The appointment could also signal further strains in what is already a cool relationship between Obama and Israeli Prime Minister Benjamin Netanyahu, who is expected to win re-election later this month.

Consternation over Hagel among Israeli policy makers stems from his professed view that there is a long way to go before negotiations with Iran should give way to more forceful policies. Hagel is also considered by some in Israel as "hostile" toward Netanyahu and has reportedly been critical of the Israeli prime minister for lobbying the U.S. to hit Iran in order to spare him of the decision. Hagel also reportedly accused Netanyahu of meddling in U.S. politics.

Hagel has voiced his support for cutting U.S. foreign aid and has said that the relationship with Israel “need not and cannot be at the expense of our Arab and Muslim relationships."

"Because of his statements in the past, and his stance toward Israel, we are worried," Knesset Speaker and Likud member Reuven Rivlin said Tuesday. But, Rivlin added, the strategic partnership between the U.S. and Israel is strong and "one person doesn't determine policy."

Netanyahu's office refused to comment on Hagel's nomination, as did officials in the Israeli foreign and defense ministries. But Rivlin's comments reflected what has been a common sentiment among analysts and commentators in Israel in recent days. In their evening news broadcasts, Israel's three main TV stations on Monday all portrayed Hagel as cool toward Israel.

Another diplomatic source in Israel, who chose to remain anonymous, said Hagel's appointment was "very bad news for Israel; it's clear that it won't be easy. It looks as if Barack Obama wants to be the good cop in his second term."

Known as a maverick in the Senate, Hagel has raised eyebrows in Israel with a series of comments and actions over the years that some here have deemed insufficiently supportive of Israel. After Hagel's nomination was leaked several weeks ago, Jewish groups expressed concern and some have even reportedly tried to derail his appointment.

Hagel once said "the Jewish lobby (in the United States) intimidates a lot of people here" and does some "dumb things" that aren't "smart for Israel." He also said that "I'm not an Israeli senator. I'm a United States senator."

"I support Israel, but my first interest is I take an oath of office to the Constitution of the United States, not to a president, not to a party, not to Israel," he said.

Six years ago, he refused to sign a letter pressing the European Union to designate the Lebanon-based Hezbollah a terrorist organization.

Hagel's call in a bipartisan letter in 2009 for a "pragmatic" approach toward Hamas, the Palestinian terrorist group that rules the Gaza Strip, has also drawn criticism. The letter called for engaging Hamas to moderate its behavior, though it said direct U.S. engagement "may not now be practical." Critics, pointing to the letter, have accused Hagel of supporting dialogue with Hamas.

Jeffrey Goldberg, a prominent journalists in the U.S. who often writes about Israel, wrote on Bloomberg.com that Hagel's confirmation hearings would be tough, but not just because of his views on Israel. Goldberg reminded readers that Hagel has often been criticized for his statements on the gay community.

"So: Is Hagel anti-Semitic?," asks Goldberg. "The short answer is no. The long answer is also no. Which is not to say that Hagel will soon win the American Jewish Committee’s Man of the Year award. He takes a tougher line on certain Israeli government policies, and a softer line on Iran, than most mainstream American politicians, but some of his views are shared by many of Israel’s left-of-center politicians and ex-military chiefs."

A former colleague of Hagel told The New York Times on Sunday that “So far, Obama’s big problem is that the threat to use force has not seemed credible."

“The question is whether if Chuck is defense secretary, the Iranians would take seriously the thought that he is willing to use force if it comes to that," the source said.

On Sunday, Hagel told his home state's Lincoln Journal Star that a close look at his past statements would suggest "unequivocal, total support for Israel," saying that his critics have "completely distorted" his views. The paper said he would use his new position to "set the record straight."

"[There is] not one shred of evidence that I'm anti-Israeli, not one [Senate] vote that matters that hurt Israel," he stressed. "I didn't sign on to certain resolutions and letters because they were counter-productive and didn't solve a problem," Hagel said. "How does that further the peace process in the Middle East?" he added. "What's in Israel's interest is to help Israel and the Palestinians find some peaceful way to live together."

"I have not supported unilateral sanctions [on Iran] because, when it is us alone, they don't work and they just isolate the United States," he told the newspaper. "United Nations sanctions are working. When we just decree something, that doesn't work.

"The distortions about my record have been astounding," Hagel added. "I have said many times that Iran is a state sponsor of terrorism. I have also questioned some very cavalier attitudes taken about very complicated issues in the Middle East. Israel is in a very, very difficult position. No border that touches Israel is always secure. We need to work to help protect Israel, so it doesn't get isolated."

While Hagel's positions on these issues are shared by many in Israel itself, including Netanyahu's own critics, they run counter to those of the Israeli prime minister and could antagonize him. Netanyahu has declared that stopping the Iranian nuclear program is his top priority. Convinced that Iran is trying to develop a nuclear bomb, a view shared in many capitals around the world, Netanyahu says Iran must be stopped. Iran says its program is only for peaceful purposes.

While voicing hope that international diplomatic pressure will halt the Iranian program, Netanyahu has said that the use of force must be seriously considered as well. Netanyahu has repeatedly threatened to attack Iran, unilaterally if necessary, if he concludes that diplomacy has failed.

Ahead of Hagel's appointment, White House officials tried to downplay such differences, saying his positions on Israel and Iran have been misrepresented and that he will be "completely in line with the president." They said that in the Senate, he voted in favor of billions of dollars in military assistance to Israel and supported multilateral sanctions on Iran.

Despite such promises, the Hagel appointment is likely to fuel the common perception in Israel that Obama does not share the warmth toward Israel held by his predecessors.

In part, that impression stems from the relationship between Obama and Netanyahu. The two leaders took office just months apart in early 2009, and from the beginning, have appeared to be at odds both on the personal level and on key policy issues.

The men have sparred over Israeli settlement policy in Judea and Samaria and east Jerusalem, the borders of a future Palestinian state and the Iranian nuclear program. Last year, Obama rebuffed Netanyahu's calls to set "red lines" that would trigger an attack on Iran. The perception here that Netanyahu favored former Massachusetts Governor Mitt Romney in the U.S. presidential election — an allegation denied by Netanyahu — has further strained ties.

The one area where relations have remained strong is in security ties. The Israeli and American defense establishments cooperate closely in monitoring the Iranians, military training and weapons development. Israel's new "Iron Dome" rocket-defense system, which performed well during the recent fighting in Gaza, was developed with American financial aid.

Speaking at a Taglit-Birthright Israel event in Jerusalem on Monday, Netanyahu thanked the U.S. for its support.

While he did not mention Hagel directly in his speech, Netanyahu did warn of dangers ahead — including Iran's nuclear program — and said "it is time for many who don't see these dangers to wake up to them."

Eytan Gilboa, a specialist on U.S.-Israel relations at Israel's Bar-Ilan University, said he thinks that Hagel "will be a total disaster for Israel."

He said Obama's choice for CIA director, John Brennan, is considered good for Israel and could be a "stabilizing factor" on U.S. policy toward Israel. But overall, he said Obama's foreign policy team creates a "potential recipe for many problems with Israel."

"Obama is sending a message to Israel that rough times are ahead and if it doesn't accommodate U.S. interests, there will be tense relations," he said.

But Dov Weisglass, who served as a top adviser to former Prime Minister Ariel Sharon a decade ago and was involved in sensitive dealings with the U.S., said concerns about Hagel are overblown.

"Ties between countries are not decided by this or that person. The ties between Israel and the U.S. are so important and complex that I don't see any reason why they should change," Weisglass said, predicting that in his new role, Hagel would, generally speaking, revise his outlook on things.

What's more, "ultimately, he is not the only decision-maker," he said.