Israeli Defense Minister Ehud Barak takes part in a panel discussion at a security conference in Munich on Sunday. Barak hinted that Israel was responsible for an airstrike on Syria last week. (TOBIAS HASE/EUROPEAN PRESSPHOTO AGENCY)

An Israeli airstrike in Syria last week targeted a shipment of weapons and caused minor collateral damage to a nearby research center that deals with chemical weapons, two U.S. officials said Sunday.

Syrian television showed images of broken glass and other damage at the Syrian Scientific Studies and Research Center, which is suspected of involvement in developing missiles to carry chemical weapons. But the video contained no evidence of a crater or the type of damage that would have been expected from a direct bombing.

Israel has not taken public responsibility for the bombing, but in remarks Sunday at a security conference in Munich, Israeli Defense Minister Ehud Barak hinted that his government was behind the attack.

“The main target was a shipment of weapons in a convoy, potentially headed to the wrong kinds of people,” said one senior U.S. military official, speaking on the condition of anonymity because of the sensitivity of the incident.

The two U.S. officials suggested that the research center north of Damascus was damaged by secondary explosions from munitions in the convoy that was the target Wednesday. The Syrian government has said the research center was the primary target.

Other Western officials and a senior Lebanese official have said that the convoy contained antiaircraft batteries that were destined for Hezbollah forces in Lebanon. The Syrian television footage showed the wreckage of what appeared to be a mobile launcher of the type used to fire SA17 antiaircraft missiles, which are known to be part of Syria’s arsenal.

In the days ahead of the strike, Israeli officials repeatedly warned that they would not allow chemical weapons to fall into the hands of the Iranian-backed Hezbollah militant group or the Islamist rebels inside Syria.

“That’s proof when we said something we mean it,” Barak said in Munich. “We say that we don’t think it should be allowed to bring advanced weapons systems into Lebanon.” But he said that he could not add information to what had been reported on “what happened in Syria several days ago.”

For years, the research center has been linked by U.S. intelligence and other experts to Syria’s missile and chemical weapons programs. It also is tied to the country’s atomic energy commission, which U.S. officials think was involved in Syria’s secret attempt to build a nuclear reactor on the Euphrates River. Israeli fighter jets destroyed the partly completed reactor in September 2007.

The attack heightened long-standing fears that the violence in Syria that has killed more than 60,000 people could spill into the rest of the volatile region.Syrian state TV ran images Saturday of damaged vehicles and a building with blown-out windows that it said was the research center.

Syrian state TV said Sunday that President Bashar al-Assad told an Iranian official that the Syrian military could “confront any aggression” toward his country, the Associated Press reported.

The head of Iran’s Revolutionary Guard Corps, Gen. Mohammad Ali Jafari, said Sunday that his government hoped Syria would retaliate, Iran’s official IRNA news agency reported.

Timeline: Major events in Syria’s tumultuous uprising that began in March 2011.

In Munich, though, Iran’s words were more peaceful. Iranian Foreign Minister Ali Akbar Salehi said Sunday that he welcomed the offer by Syrian opposition chief Mouaz al-Khatib to engage in direct talks with Assad’s government, with certain preconditions.

“I was very happy when I heard his remark that he is ready to enter into a negotiation with the representatives of the government,” Salehi said, speaking shortly after Barak, echoing praise that came a day earlier from Vice President Biden and Russian Foreign Minister Sergei Lavrov. Khatib met individually with all three officials in Munich, as well as with U.N. envoy Lakhdar Brahimi.

But Khatib’s offer does not have the unified backing of other Syrian opposition leaders, and there were few apparent breakthroughs despite the round of meetings.Khatib has come under fire for his suggestion last week, first made on his Facebook account and repeated Friday in Munich, that the opposition engage in talks with Damascus if Assad releases political prisoners and renews the passports of Syrians living abroad.

The airstrike in Syria last week was “just an indication of how rapidly this situation could escalate into a regional conflict,” Sen. John McCain (R-Ariz.) said Sunday in Munich.

Separately, Salehi said Sunday that he welcomed Biden’s offer a day earlier of direct negotiations over Iran’s nuclear ambitions. But he gave no indication that Iran was immediately prepared to take it up.

“Yes, we are ready for negotiation,” Salehi said. But he said Iran was “very firm” that “the other side this time comes with authentic intention, with a fair and real intention to resolve the issue.” He said broader talks with world powers over the nuclear issue would be held in Kazakhstan on Feb. 25.

Michael Birnbaum in Munich contributed to this report.