Any attack on Syria would be deemed an attack on Iran, a top Iranian official said Saturday in Tehran's strongest warning to date. The warning was a sign that Iran will do all it can to protect embattled Syrian President Bashar al-Assad.

Ali Akbar Velayati, an aide to Iran's Supreme Leader Ayatollah Ali Khamenei, made his comments as Syrian troops conducted offensive air raids against rebels and discovered a trio of tunnels used to smuggle weapons in their fight to topple Assad.

The world has been grappling over how to deal with Syria ever since the uprising against Assad's regime erupted nearly two years ago. But so far there has been no international intervention on the ground, where more than 60,000 people have been killed, according to the U.N.

Iran is Syria's strongest ally in the Middle East, and has provided Assad's government with military and political backing for years. In September, the top commander of Iran's powerful Revolutionary Guard, Gen. Mohammad Ali Jafari, said the elite unit had high-level advisers in Syria. Iran is also believed to be sending weapons and money to Syria as it endures its worst crisis in decades.

"Syria plays a very key role in supporting or, God forbid, destabilizing the resistance front," Velayati was quoted by Iran's semiofficial Mehr news agency as saying. "For this same reason, [an] attack on Syria is considered [an] attack on Iran and Iran's allies."

By backing the rebels trying to oust the Syrian leader, the U.S. and Arab states in the Gulf have attacked the "golden ring of resistance," Valayati said, referring to the terrorist groups Hamas and Hezbollah, and Iran and Syria, which are all anti-American.

Iran is also at odds with the international community over its nuclear program, although Iran insists it is using the program solely for peaceful purposes, not nuclear weapons.

A former Iranian diplomat who defected to the West in 2010 told Israel's Channel 2 TV in an interview broadcast on Friday that if Tehran acquired nuclear weapons, it would use them against Israel.

Mohammad Reza Heydari, who has political asylum in Norway, claimed that Venezuela was flying uranium and various components intended for use in nuclear weapons to Tehran. Venezuela backs Iran in arguing the nuclear program is purely for peaceful purposes.

Since the unrest in Syria began in March 2011, opposition forces have taken control of wide swaths of territory, mostly in the north near Syria's border with Turkey.

NATO said Saturday that the first of six Patriot missile batteries being deployed to Turkey to shoot down missiles that might come from the Syrian side of the border was now operational. The battery, meant to protect the Turkish city of Adana, was provided by the Netherlands.

The U.S., Germany and the Netherlands are providing two batteries each of the latest version of the U.S.-made Patriots. The other five Patriot batteries are expected to be operational in the coming days.

NATO says the Patriots would be used for defensive purposes only. Syria has not fired any of its surface-to-surface missiles at Turkey during the civil war, but the Assad regime has described the NATO deployment as a provocation.

The alliance also deployed Patriot batteries to Turkey during the U.S.-led invasion of Iraq 10 years ago. They were never used and were withdrawn a few months later.

Turkish Prime Minister Recep Tayyip Erdogan, interviewed on Turkish television late Friday, said the Syrian opposition now controls some 70 percent of Syria.

"If you ask me if Bashar is able endure much longer, I say, Bashar is walking, propped up from behind," said Erdogan, who was a close ally of Assad's until the crisis began. "He is losing the support of the Syrian people every day."

"At the moment Damascus is under siege. Aleppo is to a great degree already under the hands of the opposition. In other words, I can say that some 70% of the country is under the control of the opposition," Erdogan said.

In the Turkish capital, Istanbul, members of the Syrian opposition gathered Saturday to kick off a conference aimed at establishing a transitional justice system in Syria after the fall of Assad's regime. The two-day meeting was organized by the U.S.-based Syrian Center for Political and Strategic Studies.

In fighting on Saturday, Syrian forces clashing with rebels uncovered tunnels they were using to smuggle weapons and move around Daraya, a strategic suburb of the capital, Damascus, the state-run news agency said.

Syrian troops have been trying to capture Daraya for weeks, but have faced strong resistance from hundreds of rebels who have used Damascus suburbs to stage attacks on nearby government facilities.

The Britain-based Syrian Observatory for Human Rights and another activist group, the Local Coordination Committees, also reported shelling and air raids in other Damascus suburbs, including Shebaa and Aqraba near the international airport.

The LCC also said rebels fired several rockets from Daraya toward Assad's People's Palace on Qasioun Mountain, overlooking the capital. Syrian officials have previously denied claims by rebels that rockets have targeted the palace – one of three mansions Assad uses in the capital.

The activist groups also reported heavy clashes in the central city of Homs and the nearby town of Qusair, which is close to the border with Lebanon, and near a prison in the northwestern city of Idlib.

In the north, the Observatory reported two air raids: one in Al-Bab, which killed at least four people, and another in Manbij, which killed at least 12 people, including four children and women.

Doctors Without Borders, an international medical team, said a growing number of attacks in the northern province of Aleppo are likely to undermine its ability to provide medical care.

"Besides the war-wounded and the direct victims of violence, the conflict is affecting the most vulnerable, especially people with chronic diseases, women and children," said Miriam Alía, medical coordinator for the organization.