Tensions are high in the Middle East after Syria delivered a letter to the United Nations protesting the Israeli air strike on its territory and threatening a possible “surprise” response, according to Reuters.

The Syrian government may retaliate with military action. (watchsmart, Creative Commons)

The Syrian Foreign Ministry summoned the head of the U.N. force in the Israeli-occupied Golan Heights Thursday to deliver the letter, which called the strike a violation of the 1974 military disengagement agreement that followed Israel and Syria’s last major war and affirmed Syria’s right to self-defense.

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“Syria holds Israel and those who protect it fully responsible for the results of this aggression and affirms its right to defend itself, its land and sovereignty,” Syrian television quoted the letter as saying.

According to the Hezbollah-linked Lebanese website Al-Ahad, Syria’s Ambassador to Lebanon Ali Abdel-Karim Ali also stated that Syria may “decide to respond by surprise to this aggression.”

Wednesday’s air strike has been condemned by several international actors, including not only Israel’s traditional enemies, Iran and Hezbollah, but Russia as well.

“If this information is confirmed, then we are dealing with unprovoked attacks on targets on the territory of a sovereign country, which blatantly violates the UN charter and is unacceptable, no matter the motives to justify it," said the Russian Foreign Ministry in a statement Thursday.

Details remain sketchy about the strike, with Syrian state television reporting a confirmed hit at a military research center in Jamraya, several miles northwest of Damascus. Syrian media also reported two dead and five wounded from the blast. American officials, however, insist that Israel struck a weapons convoy, on its way to Lebanon with SA-17 antiaircraft missiles. Military analysts have supported this position, saying the Israeli jets’ flight patterns suggested a moving, rather than stationary, target. According to the New York Times, Israeli leaders had also warned just days before the strike that Israel would take military action to prevent any transfer of Syria’s stash of chemical weapons, which they fear will fall into the hands of Islamic terrorist organizations.

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Israeli officials have remained silent about the attack, which the Times reports is “part of a longstanding strategy to give targeted countries face-saving opportunities to avoid worsening a conflict.” Syria, however has not accepted the offer. Giora Eiland, a former Israeli national security advisor, warns that by confirming the strike, Syria may be forcing engagement.

“From the moment they chose to say Israel did something, it means someone has to do something after that,” he told the Times.

Other analysts remain unconvinced, believing that Syria is unlikely to risk its position in the fight against the Syrian uprising that has gone on for 22 months. They also point to Syria’s ally, Hezbollah, which would seek to avoid conflict with Israel in the interest of maintaining peace in neighboring Lebanon. According to Reuters, residents of Damascus have also expressed doubts of Syria’s retaliation.

“The last thing we need now is Israeli fighter jets to add to our daily routine. As if we don't have enough noise and firing keeping us awake at night," said one mother of five.

U.N. Secretary General Ban Ki-Moon has expressed “grave concern” over reports of the strike and has called on all concerned “to prevent tensions or their escalation ... and to strictly abide by international law, in particular in respect of territorial integrity and sovereignty of all countries in the region.”

For now, however, the U.N. has held off on Syria’s demand that it condemn the air strike. The U.N. continues to provide humanitarian assistance to Syria in its time of violent political unrest, having secured pledges of over $1.5 billion in aid from countries and regional organizations to address the crisis mere hours before the strike occurred Wednesday.

Find more Neon Tommy coverage on Syria here.

Reach Executive Producer Francesca Bessey here.