A massive explosion lights up the night sky in Damascus (Image from YouTube)
New videos posted overnight show dramatic and powerful explosions that occurred on the outskirts of Syria's capital Damascus early Sunday morning.
Syria's state television is blaming Israel for striking the military research center in Jamraya just north of Damascus. Israeli officials are not commenting publicly, but a senior U.S. official tells NBC News that Israel was behind the attack.
"The new Israeli attack is an attempt to raise the morale of the terrorist groups which have been reeling from strikes by our noble army," Syrian television said.
A woman who lives in Damascus told Al Jazeera that she heard a rocket whizzing by after which "everything started to shake."
"We heard a very huge explosion like 'boom'" which blew the doors open, she said.
In this video which is described as overlooking Qasioun Mountain, an initial explosion is followed by a second and then a dramatic, massive third explosion. Qasioun Mountain is a place where military assets belonging to government forces loyal to the embattled President Bashar Assad are situated.
It is likely Assad opponents filmed the scene, as cries of "Allahu Akbar" are heard in the background.
This video was apparently taken from another angle, from which it's possible to see a mushroom-shaped cloud rising into the night sky:
Another Damascus resident tells Al Jazeera the explosion was "unprecedented" in force and felt like "an earthquake."
Damascus resident Tarek Hillnawi was sitting on his balcony with friends when the explosion occurred. He tells Al Arabiya: "Everything was quiet and suddenly we saw this bright orange light in the sky followed by a very loud explosion."
"I felt that it was over for us, that all of Damascus is set on fire," he added.
Al Arabiya reports that "at least 40 blasts were heard across the capital following the alleged Israeli attack."
The Syrian Observatory for Human Rights spoke to eyewitnesses who reported seeing jets in the sky when the explosions occurred.
A Syrian official tells Al Arabiya that Assad's forces use their strategic position on Qasioun Mountain to shell rebels in the capital's different neighborhoods and suburbs.
"The mountain is a very strategic site that oversees all of Damascus," said the source. "There is a heavy presence of the Assad forces in the mountain because they are always on-call to launch any possible attack towards the people of the city."
Syria expert Andrew J. Tabler of the Washington Institute for Near East Policy tells the New York Times: "They are definitely going after military facilities on or around Qasioun."
"There are a lot of research and military facilities there that are tied into the command and control structure of the regime," he said.
"It is unprecedented and something all of Damascus can see," he added.
If Israel was involved, it would be the second time in recent days that Israel has bombed Syria, a development the Washington Post describes as "a sharp escalation in tensions between the neighboring countries." The Israel Defense Forces targeted the same military research facility in January.
Several hours after the Syria attack on Sunday, the IDF deployed two Iron Dome anti-missile batteries in northern Israel, one in Haifa and one in Safed. Israeli media report that this protective measure is meant to defend against any potential retaliation from Syria or from Hezbollah in Lebanon.
The Post suggests that President Bashar Assad could decide this time to respond to Israel, something he has refrained from doing until now, focusing instead on battling the two-year insurgency spearheaded by Sunni radicals. It reports on the ominous tone conveyed by Syria's government broadcaster:
The official Syrian Arab News Agency said that a scientific research facility had been struck by an Israeli missile, and a banner displayed on state television said the attack was intended to relieve pressure on rebel forces in the embattled eastern suburbs. The banner was accompanied by martial music and footage of Syrian soldiers marching, descending from helicopters and firing rockets, indicating that Syria may not shrug off the assault, as it has with some Israeli strikes in the past.
"The Israeli aggression comes at a time when our armed forces are scoring victories against terrorism and al-Qaeda gangs," state television said.
On Friday, an Israeli airstrike targeted a shipment of advanced Iranian surface-to-surface missiles heading for Hezbollah in Lebanon via Damascus, according to U.S. officials quoted by the New York Times. The paper's reporting highlights the gravity of the threat for Israel:
An American official, who asked not to be identified because he was discussing intelligence reports, said the targeted shipment consisted of Iranian-made Fateh-110s -- a mobile, accurate, solid-fueled missile that has the range to strike Tel Aviv and much of Israel from southern Lebanon, and that represents a considerable improvement over the liquid-fueled Scud missile.
Israeli officials have been watching the strife in Syria with growing concern and have emphasized they would use force to make sure President Bashar Assad's large stockpile of chemical weapons and advanced missiles don't fall into the hands of Hezbollah or radical jihadi rebels.
President Obama told Telemundo before the Sunday strike, "The Israelis, justifiably, have to guard against the transfer of advanced weaponry to terrorist organizations like Hezbollah."
The New York Times notes that American officials have described the Jamraya complex, also known as the Syrian Scientific Studies and Research Center, as "Syria's main research center for work on biological and chemical weapons."
During the two-year conflict between Assad's forces and the rebels, an estimated 70,000 people have been killed according to the United Nations.
This story has been updated.