Israeli strikes have hit an arms depot operated by the Lebanese Hezbollah group near Damascus airport, Syrian opposition sources said.
Witnesses said a total of five strikes occurred near the Damascus airport road, about 25km from the capital, early on Thursday.
Syrian state TV quoted a military source saying rockets fired from Israeli territory targeted a military area in the south-western part of the airport which caused explosions.
A news agency, citing an intelligence source, said the depot that was targeted handles a significant amount of weapons that Tehran, a major regional ally of Syrian President Bashar al-Assad, sends regularly by air.
The source said the arms depot gets a major part of the weapons supplied to an array of Iranian backed armed groups, led by Hezbollah, which have thousands of fighters engaged in battle against Syrian rebels.
Rami Abdurrahman, head of the UK-based Syrian Observatory for Human Rights, said the blasts were heard across the capital, jolting residents awake.
Activist-operated Diary of a Mortar, which reports from Damascus, said the explosions near the airport road were followed by flames rising above the area.
'Unacceptable'
The Kremlin strongly criticised Israeli air strikes on targets inside Syria on Thursday, saying Israel and other countries should avoid any action that heightened tension in the region.
"We consider that all countries should avoid any actions that lead to higher tensions in such a troubled region and call for Syrian sovereignty to be respected," Kremlin spokesman Dmitry Peskov told reporters, when asked about the attack.
Russia and Israel were in constant contact about the situation in Syria through various channels, said Peskov.
