BEIRUT: Lebanese leaders on both sides of the political spectrum condemned Thursday an alleged Israeli airstrike on a military target in Syria as Damascus threatened retaliation against the Jewish state.

Syrian Ambassador to Lebanon, Ali Abdel-Karim Ali, warned that his country has “the option and the capacity to surprise in retaliation.” He said he could not predict when the retaliation would take place, according to the Associated Press, adding it was up to relevant authorities to prepare for it.

Syria could take “a surprise decision to respond to the aggression of the Israeli warplanes,” Ali told a website of Hezbollah. “Syria is engaged in defending its sovereignty and its land.”

In 2007, a Syrian threat to avenge an Israeli airstrike on a suspected Syrian nuclear site was never carried out.

On Wednesday, the Syrian army accused Israel of launching a strike on a military research facility in the area of Jamraya, near Damascus, about 15 kilometers from the Lebanese border. Syrian state television said two people were killed in the raid, describing the target as a scientific research center.

Israeli officials and the military refused Thursday to confirm or deny any involvement in the alleged attack. They also gave no comment on alternative reports that its warplanes had struck a weapons convoy along the Syria-Lebanon border.

President Michel Sleiman denounced the airstrike in Jamraya, accusing Israel of using the 22-month-old turmoil in Syria to carry out its “aggressive policies.”

“Israel is exploiting the current situation in Syria to implement its aggressive policies, flouting international treaties and humanitarian rights and norms,” Sleiman said in a statement released by his office.

The president discussed the alleged Israeli raid during a meeting Thursday with U.S. Ambassador to Lebanon Maura Connelly at Baabda Palace.

Hezbollah, a key ally of Syrian President Bashar Assad, condemned the supposed Israeli attack, calling on Syrian opposition and rebel groups to reconsider their positions and use dialogue as the only means to resolve the 22-month-old crisis in Syria.

Hezbollah said the alleged Israeli attack was aimed at preventing Arab and Muslim forces from developing their military capabilities.

“This attack reveals in a flagrant manner the motives behind what has been happening in Syria over the past two years and its criminal dimensions aimed at destroying Syria and its army and eliminating its pivotal role in the resistance front,” a statement said.

It added that the “barbaric Israeli attack” should evoke the broadest campaign of condemnation by the international community and all Arab and Muslim countries.

In an appeal to Syrian opposition groups to enter talks with the regime, the statement said: “Hezbollah, which expresses its full solidarity with Syria’s leadership, army and people, underlines the need for some to be wary of the gravity behind targeting Syria, and to use this aggression as an occasion to review their stances and adopt political dialogue as the only basis for a solution in order to protect Syria and safeguard its role and position in confronting enemies.”

Lebanese Foreign Minister Adnan Mansour condemned the Israeli strike. “This aggression again confirms the reality of Israel’s conduct by which the state of terrorism has been characterized since 1948,” he said. He called for a firm stance by Arab countries to confront the attack.

The airstrike was also condemned by former Prime Minister Fouad Siniora, head of the parliamentary Future bloc, which supports the armed revolt against the Assad regime.

“Our stance on developments in Syria is known. But a serious development happened yesterday in the form of an Israeli air attack on Syrian territory and positions. This matter is condemned and rejected,” Siniora said in a statement. “We cannot accept an attack by the Israeli enemy on any Arab territory.”

Sheikh Abdel-Amir Qabalan, deputy head of the Higher Shiite Council, said the purported Israeli strike “once again reveals the extent of the conspiracy against Syria, its people, army and institutions.”

The head of the Amal Movement, Speaker Nabih Berri, said the attack amounted to an Israeli intervention in the Syrian conflict with the aim of sabotaging any possible chance to resolve the crisis.