Israel strike on Syria killed at least 15 soldiers - NGO
"At least 15 soldiers were killed, and dozens more are missing" after the strikes near Damascus early on Sunday, said the Observatory's Rami Abdel Rahman.
"These three sites (targeted) would usually have around 150 soldiers in them, but it's not clear if they were all there at the time of the strikes."
A series of massive explosions illuminated the dark sky over Damascus early Sunday, igniting renewed claims that Israel has launched attacks into the war-torn country.
Syria's government said the explosions were the second Israeli airstrike in three days. The latest target, officials said, was a military research facility outside the Syrian capital. A top Syrian official told CNN in an exclusive interview that the attack was a "declaration of war" by Israel.
Syrian authorities vowed to retaliate against Israel but did not specify what action they would take.
The Israeli military would not confirm or deny the Syrian claim that Israel fired rockets that hit the Jamraya research center in the Damascus suburbs.
"We do not comment on these reports at all," an Israeli military representative said.
United Nations Secretary-General Ban Ki-moon
Sunday's explosions mark the third time Israel has been accused of striking inside Syria this year.
The United States was not given any warning before air strikes in Syria against what Western and Israeli officials say were weapons headed for Hezbollah militants, a U.S. intelligence official said on Sunday.
Without confirming that Israel was behind the attacks, the U.S. intelligence official said that the United States was essentially told of the air raids "after the fact" and was notified as the bombs went off.
United Nations Secretary-General Ban Ki-moon warned against escalating the situation in Syria after
Israeli officials said the raid, the second in 48 hours, was not connected to Syria's civil war. It was aimed, rather, at stopping Lebanon's Hezbollah, an ally of Iran, acquiring weapons that could be used to strike Tel Aviv if Israel followed through on threats to attack Iranian nuclear facilities.
According to Syrian reports Israel targetted an arms depot, a research center and two brigades of presidential guards and killed over 300 soldiers.
Voice of Russia, AFP, Reuters, Damaspost.com, DPA, CNN