Russia’s movement of tactical aircraft and surface-to-air missiles to Syria could pose a threat to American and allied forces, says US Secretary of State John Kerry.

US officials report Russia moved a small number of fighter jets to a base in Syria yesterday.

The move came just hours after US Defense Secretary Ash Carter talked with Russia Defense Minister Sergei Shoigu in the first military contacts between the two countries in some time.

Tensions have been high between the US and Russia since the invasion of Crimea and Moscow’s thinly disguised support for Ukrainian rebels.

“Clearly, the presence of aircraft with air-to-air combat capacity ... and surface-to-air missiles raise serious questions,” Kerry said, responding to a question after meeting with British Foreign Minister Philip Hammond.

RUSSIA ‘TO FIGHT ISIS’

Russia says its recent military build-up in Syria is designed to fight the Islamic State group and fulfil its obligations under its alliance with Syria. While IS lacks an air force, the Russian aircraft are capable of striking ground targets and providing close air support for ground forces, a US intelligence official said.

The combat aircraft are believed to be ground-attack versions of the Su27 Flanker strike fighter.

Sat images - #Russia has 4 Su-27 jets, 2 Mi-24 & 2 Mi-17 choppers, 6 T-90 tanks & 25+ BTR APCs in #Latakia airbase: pic.twitter.com/sPOdgi1Ms8 — Charles Lister (@Charles_Lister) September 19, 2015

This is the same role being conducted by Australia’s F/A-18 fighters which were only a week ago authorised to extend their operations beyond Iraq and into Syria. The Combined Joint Task Force Operation Inherent Resolve this morning listed details of a string of attacks in Syria, stating Australian aircraft had taken part.

Concerns have been raised about the potential for an ‘incident’ between uncoordinated combat jets operating in the same area at the same time. This may become a particular problem for Britain’s Royal Air Force, which regularly flies over Assad strongholds in Syria’s west from its base in Cyprus.

Russia’s recent military moves in Syria are its first major expeditionary force deployment outside the former Soviet Union since the war in Afghanistan.

Kerry says military-to-military talks with the Russians are designed to make sure there are no incidents between Russian and allied forces. The discussions also amount to a tacit acceptance of the Russian build-up, after weeks of warnings from Washington against any Russian escalation in Syria.

Meanwhile, a Syrian rebel group claims it fired rockets at a coastal air base said to be used by Russian troops. In a video posted yesterday, members of the Islam Army warn the Russians that they will not enjoy peace in Syria. The fighters are then are seen loading and launching multiple rockets from a mountainous area.

US BACKDOWN ON ASSAD

In another apparent concession, Kerry stated explicitly that the US could accept a resolution to the Syrian war that allowed President Bashar Assad to remain in place for a time before departing, as the US long has wanted.

“We’re not being doctrinaire about the specific date or time - we’re open,” Kerry said, adding that Assad doesn’t have to leave “on day one, or month one, or whatever.”

He later added that the US considered Assad a magnet for the foreign fighters who are filling the Islamic State group’s ranks.

“So there’s a lack of logic,” Kerry said, for the Russians to say “they are bringing in more equipment to shore up Assad at the same time they say they are going after” the militants.”

“(But) is Assad prepared to negotiate, really negotiate? Is Russia prepared to bring him to the table and actually find the solution to this violence?”

Kerry and Hammond said they also discussed the situations in Yemen, Libya and Ukraine. Kerry also urged restraint in response to days of clashes around the Jerusalem holy site known to Muslims as the Noble Sanctuary and to Jews as the Temple Mount.

“All of us join together in urging everybody to keep the calm,” Kerry said.