Israeli warplanes bombed two areas near Damascus on Sunday, striking near the city's international airport as well as outside a town close to the Lebanese border, the Syrian military said.

Since Syria's conflict began in March 2011, Israel has carried out several airstrikes in Syria that have targeted sophisticated weapons systems, including Russian-made anti-aircraft missiles and Iranian-made missiles, believed to be destined for Israel's arch foe - the Lebanese Hezbollah militant group.

Israel has never confirmed the strikes, and on Sunday the Israeli military said it does not comment on "foreign reports."

The Syrian armed forces' general command said Sunday's "flagrant attack" caused material damage, but did not provide any details on what was hit near the airport or in the town of Dimas, which is northwest of Damascus along the main highway from the capital to the Lebanese frontier.

Airports, weapons depots targeted

"This aggression demonstrates Israel's direct involvement in supporting terrorism in Syria along with well-known regional and Western countries to raise the morale of terrorist groups, mainly the Nusra Front," the military said in a statement carried by SANA.

There is no evidence that Israel has provided any support to the Nusra Front, which is al-Qaeda's affiliate in Syria.

The director of the Syrian Observatory for Human Rights, Rami Abdurrahman, said the strike near the Damascus international airport targeted a depot for newly arrived weapons at a military facility that is part of the airport.

The strikes near Dimas, he said, went after weapons depots in hangars in and around a small air base. It was not clear whether those weapons were for the Syrian government or for Hezbollah. He had no word on casualties.

The Britain-based Observatory monitors Syria's civil war through a network of activists on the ground.

While Israel has tried to stay out of the war in neighbouring Syria, Prime Minister Benjamin Netanyahu has repeatedly threatened to take military action to prevent Syria from transferring sophisticated weapons to its ally Hezbollah. Israel and Hezbollah are bitter enemies and fought an intense monthlong war in 2006.

In May 2013, a series of Israeli airstrikes near Damascus targeted what Israeli officials said were shipments of Iranian-made Fateh-110 missiles bound for Hezbollah.

Syrian airstrikes target ISIS

In eastern Syria on Sunday, Syrian warplanes carried out at least 11 airstrikes of their own against Islamic State of Iraq and Syria (ISIS) militants attacking a key military air base, activists said.

ISIS launched its assault on the sprawling air field just outside of the city of Deir el-Zour last week, touching off fighting that activists say has killed more than 150 people on both sides. For ISIS, seizing control of the base would eliminate the last significant government presence in the area and provide a major morale and propaganda boost.

The Local Coordination Committees activist collective and the Observatory said the strikes targeted four areas near the base.

After ISIS fighters succeeded in storming part of the base on Saturday, the Syrian military launched a counterattack — bolstered by heavy air raids — that managed to push the militants back. Scattered clashes on the ground continued Sunday with fighting on several fronts around the base, activists said.

A Syrian military official in Damascus told The Associated Press that troops are in full control of the base.

"They (ISIS) tried to launch attacks from their positions around the airport but they were countered, and tens of them were killed and large amounts of weapons were seized," he said, speaking on condition of anonymity because he was not authorized to brief the media.