An Israeli missile strike has caused a large explosion and fire at a military site near Damascus international airport, Syrian state media report.
A fuel tank and warehouses were damaged, the Sana
news agency said.
But Syrian rebel sources said an arms depot run by Lebanon's Hezbollah movement, which is fighting in Syria as an ally of the government, was hit.
Israel said the explosion was "consistent" with its policy to prevent Iran smuggling weapons to Hezbollah.
But it stopped short of confirming it was responsible.
Israel regards Hezbollah, and its key backer Iran, as its biggest threat. It went to war with Hezbollah in 2006 and the group has grown considerably more powerful since then.
The Syrian Observatory for Human Rights, a UK-based monitoring group, reported that the powerful blast was heard across the capital at dawn on Thursday and that it was believed to have happened near the main road that leads to the airport.
Sana said several missiles had been fired at a military site south-west of the airport, causing explosions that resulted in some material losses.
Pro-government Al-Mayadeen TV
cited sources as saying that missiles had been fired by Israeli jets flying inside the Israeli-occupied Golan Heights.
Two senior rebel sources based in Damascus told Reuters
news agency that the missiles had hit an ammunition depot in a closed military area that was used by Iran-backed militias operating alongside the Syrian army, led by Hezbollah.
Appearing to confirm Israeli involvement, Intelligence Minister Israel Katz told Israeli Army Radio
: "I can confirm that the incident in Syria corresponds completely with Israel's policy to act to prevent Iran's smuggling of advanced weapons via Syria to Hezbollah in Iran. Naturally, I don't want to elaborate on this."
"The prime minister has said that whenever we receive intelligence that indicated an intention to transfer advanced weapons to Hezbollah, we will act."
The Israeli military declined to comment on the reports.