Syria’s Deputy Foreign Minister Faisal Mekdad warned Sunday that recent Israeli airstrikes on facilities near Damascus constituted an Israeli “declaration of war.”

Mekdad’s comments prompted concern in Israel about a possible escalation of hostilities between Israel and Syria, and Israel was said to be braced for all possibilities. But Prime Minister Benjamin Netanyahu was still intending to head to China for four days on Sunday night, in what was partly a demonstrative desire to play down the likelihood of escalation.

Mekdad made the statement during an interview with CNN on Sunday, hours after Israel reportedly struck military targets on the outskirts of Damascus for the second time in 48 hours.

The Foreign Ministry in Damascus stated in a letter to the United Nations that the strikes “killed and wounded several people.”

Syria’s Information Minister Omran al-Zoubi said soon afterward that “all options are open” for Syria to respond to the attacks, which he claimed conclusively demonstrated the alliance between “the terrorists, infidels and Zionists” fighting the regime of President Bashar Assad. Still, in more moderate tones, al-Zoubi also said the regime’s priority was to battle the forces inside Syria that were challenging the regime, and he denied claims in some Arab media that an Israeli plane had been shot down by Syrian forces and two pilots captured.

Mekdad had also asserted that the attacks reflected an alliance between Islamic terrorists fighting against Assad’s regime and Israel, and warned that Syria would retaliate as and when it saw fit.

Syrian officials made similar threats after an alleged Israeli airstrike on a weapons convey near the Lebanese-Syrian border at the end of January 2013.

The Foreign Ministry in Damascus said the attacks aimed “to give direct military support to terrorist groups” fighting the government.

In its letter sent to the United Nations and the UN Security Council, the ministry also said that the “Israeli aggression” killed and wounded several people and “caused widespread destruction.”

Egypt and the Arab League condemned the strike, with Cairo’s Foreign Ministry saying it was against any infraction of the sovereignty of Arab countries.

Apparently bracing for possible retaliation, Israel deployed two Iron Dome missile defense batteries in the north of the country on Sunday morning, hours after it reportedly struck a shipment of Iranian missiles bound for Hezbollah near Damascus.

One Iron Dome battery was deployed in Safed and the other in Haifa. The Iron Dome system has proved highly effective in stopping short-range rocket fire, intercepting 84 percent of the incoming rockets from Gaza it aimed at during Operation Pillar of Defense last November.

A Syrian state TV report claimed Israeli rockets hit a military research site on the outskirts of the capital at about 2 a.m., while an unnamed Israeli official told AFP the target was a shipment of Iranian made Fateh-110 missiles that were on their way from Syria to Hezbollah terrorists.

Netanyahu convened his security cabinet on Sunday afternoon to discuss the escalating hostilities with Syria. He delayed his scheduled Sunday evening departure for China by two hours in order to participate in the meeting.

The fact that Netanyahu was nonetheless going ahead with the China trip, diplomatic sources said, underlined Israel’s intention to de-escalate tensions with Syria. Furthermore, the sources said, the fact that Israel was privately stressing that the missiles hit in the strike came from Iran, and were intended for Hezbollah, and that Israel reportedly did not enter Syrian airspace but rather carried out the strikes from inside Lebanese air space, was intended to reduce the focus on Syria and thus reduce the likelihood of a Syrian military response.

Army Radio reported Israeli concerns that Hezbollah might seek further Iranian missile shipments, and said the security establishment was therefore remaining on alert.

Israel’s Channel 2 said Sunday evening that Hezbollah was engaging in “psychological warfare,” trying to further escalate tensions between Israel and Syria. The Assad regime was deploying long-range missiles to face Israel, and would now seek even more energetically to supply Hezbollah with unprecedentedly advanced weaponry, Hezbollah claimed, according to the Channel 2 report, which noted that there was no confirmation of these assertions.

There were no official Syrian reports on casualty numbers in either of the two strikes Friday and Sunday. An unconfirmed report on the Russia Today website cited a local Syrian journalist reporting “rumors on Syrian social media” that 300 or more soldiers stationed at military bases on Mount Qassiyoun near Damascus were killed. “Many Syrians are calling for retaliation as the possibility of a full-scale war with Israel is speculated upon,” this unconfirmed report further claimed.

Activists opposed to the Assad regime reported that a blast hit an ammunition depot in the Qassiyoun mountains late Saturday. It was not clear if that reported incident was related to any Israeli activity. According to a Syrian official who spoke to Al Arabiya, the Syrian regime uses its bases on the mountain to fire missiles at rebel targets in Damascus.

MK Tzachi Hanegbi (Likud), a former chairman of the Knesset’s Foreign Affairs and Defense Committee, said Sunday it was unlikely Syria would hit back at Israel, but did not rule this out. “A Syrian retaliation is always an option,” he conceded, “but apparently it was deemed to be a long shot.”

“Iran is testing Israel’s and the US’s determination to uphold ‘red lines.’ And what it is seeing in Syria is that at least some of the actors take red lines seriously,” said former IDF intelligence chief Amos Yadlin.

Iran’s Foreign Ministry spokesman condemned Sunday’s Israeli airstrike, but gave no hint of a possible stronger response from Tehran or its allies.

Ramin Mehmanparast was quoted Sunday by the semiofficial Fars news agency denouncing the attack on the Iranian missiles, which were believed en route to Iranian-backed Hezbollah in Lebanon. His were the first Iranian comments since Israel launched a first round of airstrikes on Friday.

Mehmanparast urged countries in the region to remain united against Israel.

“As a Muslim nation, we back Syria, and if there is need for training we will provide them with the training, but won’t have any active involvement in the operations,” Iranian general Ahmad Reza Pourdastan said in remarks reported by the official IRNA news agency.

“The Syrian army has accumulated experience during years of conflict with the Zionist regime and is able to defend itself and doesn’t need foreign assistance,” he added.

Uzi Rubin, a missile expert and former Defense Ministry official, told the Associated Press that if the target of the reported strikes was a consignment of Fateh-110 missiles, then such weaponry did constitute a “game-changer”: Fired from Syria or south Lebanon, these missiles, he said, could reach almost anywhere in Israel with high accuracy.

“All countries have to look after their own national security, of course, and are able to take actions to protect their own national security,” Britain’s Foreign Secretary William Hague told Sky News Sunday.

He said the attack showed that Syria’s two-year-long civil war risked spreading outside its borders to engulf the entire region, and argued it was time to consider lifting the arms embargo on Syria’s opposition.

“The longer this goes on, the stronger the case becomes for lifting the arms embargoes on the National Coalition, on the Syrian opposition, if we’re left with no other alternative to that,” Hague said.

AP contributed to this report.