Prime Minister Benjamin Netanyahu urged the international community on Wednesday to threaten Iran with "military sanctions," saying economic measures were failing to curb Tehran's nuclear drive.

"I believe it is incumbent upon the international community to intensify the sanctions and clarify that if Iran continues its program, there will be military sanctions," Netanyahu said in a statement released by the Prime Minister's Office,

He did not specify what military measures he envisaged, although one example could be a naval blockade of Iran.

"I don't think there are any other means that will make Iran heed the international community's demands," he said, in his first remarks on the issue after two days of nuclear talks between Tehran and world powers in the Kazakh city of Almaty.

Netanyahu has long said that only a credible military threat, coupled with tough economic sanctions, can dissuade Iran from acquiring what Israel and the West believe is a capability to build nuclear weapons.

Iran insists it is enriching uranium for peaceful purposes only.

In Almaty, the first negotiations between Iran and six world powers in eight months ended without a breakthrough on Wednesday. They agreed to meet again at expert level in Istanbul next month and resume political talks in Kazakhstan on April 5.

Iranian negotiating team head Saeed Jalili described this week's talks as "positive" and said that what the world powers had proposed in this round was "more realistic" than previous offers. He even termed the current round of talks a "turning point."

But Western officials cautioned that the negotiations did not constitute major progress. European Union foreign policy chief Catherine Ashton, who headed the negotiations on behalf of the Western powers, voiced hope that the Iranians would look favorably on the new proposal, but also said she believed in "looking at what the results are."

Off the record, Western officials remarked that in essence, the negotiations had not yet begun. One American official told The New York Times that in his view, the new proposal was no "softer" than the previous one. He did concede, however, that the new proposal offered a more comprehensive lifting of sanctions in exchange for Iranian cooperation. In the meantime, Western officials said, the pressure on Iran will continue to grow until the crisis is resolved.

But while the White House is trying to advance negotiations, Congress is stepping up efforts to tighten sanctions on Iran. U.S. lawmakers introduced legislation on Wednesday that would allow the president to impose penalties on foreign entities that provide Iran with goods, the French news agency AFP reported.

The bipartisan bill would also expand the president's authority to target strategic imports like mining equipment or power generating equipment, which could help Iran with its nuclear aspirations.

Beyond increasing sanctions, the new bill proposes classifying Iran's Revolutionary Guard as a terrorist organization, though it is not clear what such classification would entail since such labels are usually assigned by the State Department.