Israeli warplanes struck areas in and around the Syrian capital, setting off a series of explosions as they targeted a shipment of highly accurate, Iranian-made guided missiles believed to be on their way to Lebanon's Hezbollah group, officials and activists said.

Syria's state media on Sunday reported that Israeli missiles struck a military and scientific research centre near the Syrian capital and caused casualties.

The attack, the second in three days, signaled a sharp escalation of Israel's involvement in Syria's civil war.

"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, referring to recent offensives by the forces of Bashar al-Assad, the Syrian president, against the armed opposition.

A Western intelligence source confirmed the attack to The Associated Press, saying the target of Sunday's strike was a shiptment of advanced guided Iranian-made missiles, believed to be on their way to Lebanon's group Hezbollah.

Video footage uploaded onto the internet by activists showed a huge ball of fire rising into the night sky.

Later on Sunday, the Syrian government condemned the airstrikes, saying the attacks aim "to give direct military support to terrorist groups" fighting the government.

The Syrian Foreign Ministry also said in a letter sent to the United Nations and the UN Security Council that the "Israeli aggression" killed and wounded several people and "cause widespread distruction".

'Felt like an earthquake'

A Damascus resident described the blasts to Al Jazeera, saying they felt like "an earthquake" and "unprecedented".

Fawaz Gerges, political analyst, discusses the potential fall out following the Israeli airstrikes on Syria

A senior Israeli source told AFP that Israel had carried out the airstrike, which they said struck near Damascus airport.

"The attack was very close to hte airport, the target was Iranian missiles which were destined for Hezbollah," he told AFP, speaking on condition of anonymity.

The US State Department had no immediate comment and the Israeli embassy in Washington declined comment.



The Syrian state media claims, reported by the Reuters news agency, come after Israel confirmed that its air force hit a shipment of missiles in Syria bound for Hezbollah.

Israel has repeatedly said that it is prepared to resort to force to prevent Syrian weapons, including chemical weapons, from reaching Hezbollah or groups.

Syria's rebel Free Syrian Army reacted cautiously on Sunday to the Israeli air strikes, saying their country was already under attack daily by regime war planes.

"Of course the Free Syrian Army and any Syrian is bothered that their country is being bombed, but Syria is being bombed every day by (President) Bashar al-Assad, and by Israel," FSA media and political coordinator Louay Meqdad told.

He spoke after Syrian state media reported that Israeli rockets struck a military facility outside the capital Damascus overnight, the second reported attack by the Jewish state inside Syria this week.

"We wonder why there are so many missiles and military installations around Damascus when they should be close to the ceasefire line with Israel on the Golan Heights," he added.

"For us, the operations that we carry out every day are not related to Israeli attacks or anything else, and we will continue to fight until the fall of Assad," he said.

The US president, Barack Obama, said on Saturday, before the latest incident, that it was up to Israel to confirm or deny any strikes, but that the US coordinated very closely with Israel.

"The Israelis, justifiably, have to guard against the transfer of advanced weaponry to terrorist organizations like Hezbollah," Obama told the Spanish-language TV station Telemundo.