According to the officials, Russia has sent 12 SU-24 attack aircraft, 12 SU-25 ground attack aircraft (seen in picture) and four Flanker fighter jets.

Russia has increased its deployment of warplanes to Syria but so far they appear to be positioned to defend their own base rather than to mount an offensive campaign, U.S. Secretary of State John Kerry said Tuesday.

“Yes, they have increased aircraft and there are certain kinds of aircraft there which, depending on what Russia’s decision is about its long-term intentions, could raise questions,” Kerry said.

“But for the moment, it is the judgment of our military and most experts that the level and type represents basically force protection for their deployment to an airbase, given the fact that it is in an area of conflict.”

Kerry, however, said Russian and Iranian support for Syrian President Bashar Assad is misplaced and will only prolong the war. But he said the U.S. is ready to engage in an immediate dialogue with Russia to promote a peace agreement that would see Assad removed from power.

Meanwhile, Damascus has received new warplanes and reconnaissance aircraft from Moscow to fight against the Islamic State of Iraq and Syria (ISIS) group, a Syrian military source told AFP on Tuesday.

“Our air force has taken delivery of at least five fighter planes from Moscow as well as reconnaissance aircraft which allow us to identify targets with great accuracy,” the senior official told AFP on condition of anonymity.

The source said the aircraft had arrived on Friday at a military base in Latakia province, the traditional heartland of Assad’s regime.

Moscow has also delivered other “sophisticated military equipment to fight ISIS,” the official said.

“These are defensive and offensive weapons” including “sophisticated arms that target with accuracy and precision-guided missiles,” the official said.

“Russian weapons are starting to have an effect in Syria,” the official said.

“The Syrian military has started using them in the cities of Deir Ezzor and Raqa, in particular against ISIS positions,” the official said.

Another military source in Latakia told AFP the army had “received Russian reconnaissance planes that will allow Syrian ground and air forces to accurately identify targets.”

The deliveries also included “radars and infra-red binoculars,” the source said.

On Monday, U.S. officials said Russia has deployed 28 combat planes in Syria, confirming the latest move in Moscow’s increasing military presence in the war-torn nation.

U.S. says Russia deployed 28 combat planes

Russia has deployed 28 combat planes in Syria, U.S. officials said on Monday, confirming the latest move in Moscow’s increasing military presence in the war-torn nation.

Washington in recent weeks has expressed growing concern over Russia’s moves to support President Assad and warned that militarily backing his regime risks further hampering efforts at bringing peace.

Experts said the buildup is likely a prelude to military action.

This kind of aircraft suggests that the Russians intend to exert their combat power outside of Latakia in an offensive role.

Jeffrey White, Analyst at the Washington Institute for Near East Policy

“There are 28 fighter and bomber aircraft” at an airfield in the western Syrian province of Latakia, one of the officials told AFP, speaking on condition of anonymity.

A second official, also speaking on condition of anonymity, confirmed the figure and added there were also about 20 Russian combat and transport helicopters at the base.

That official also said Russia was operating drones over Syria, but did not give additional details.

According to the officials, Russia has sent 12 SU-24 attack aircraft, 12 SU-25 ground attack aircraft and four Flanker fighter jets.

Analyst Jeffrey White of the Washington Institute for Near East Policy said: “They are not going to sit around and defend the airfield or maybe even the province of Latakia.

“This kind of aircraft suggests that the Russians intend to exert their combat power outside of Latakia in an offensive role.”

Moscow has been on a diplomatic push to get the coalition of Western and regional powers fighting the Islamic State of Iraq and Syria (ISIS) group in Syria to join forces with Assad against the extremists.

The U.S.-led coalition is carrying out almost daily strikes against the ISIS extremists in Syria.