The United States and Russia have renewed high-level military contacts to discuss mechanisms in order to avoid accidental encounters between their forces in Syria, the Pentagon says.

US Secretary of Defense Ash Carter and his Russian counterpart Sergei Shoigu spoke by telephone on Friday, according to Pentagon spokesman Peter Cook.

"The secretary and the minister talked about areas where the United States and Russia's perspectives overlap and areas of divergence," Cook said.

"They agreed to further discuss mechanisms for deconfliction in Syria and the counter-ISIL campaign," he stated, using a military term, deconfliction, which means rival armies will talk to one another in order to avoid accidental encounters between their forces.

The United States and Russia broke off direct military contacts in April 2014 over a dispute over the crisis in Ukraine.

"The secretary emphasized the importance of pursuing such consultations in parallel with diplomatic talks that would ensure a political transition in Syria," Cook said in a statement.

"He noted that defeating ISIL and ensuring a political transition are objectives that need to be pursued at the same time,” the Pentagon spokesman said, referring to the Daesh terrorist group. “Both the secretary and the minister agreed to continue their dialogue."

Moments earlier, US Secretary of State John Kerry said during a visit to London that "military-to-military" discussions between the US and Russia on the Syrian crisis will begin shortly.

"The president believes that military-to-military conversation is an important next step and I think hopefully it will take place very shortly," Kerry said on Friday.

"Obviously our focus remains on destroying ISIL and also on a political settlement with respect to Syria," he stated, using an acronym for the terrorist group.

On Thursday, the White House said there is no military solution to the years-long Syrian crisis and sought cooperation from Russia to address the deadly unrest in the Arab country.

Washington "remains open to tactical, practical discussions" with Moscow over the fight against the Daesh (ISIL) terrorist group in Syria, White House spokesman Josh Earnest told reporters.

The White House remarks came following Moscow's alleged deployment of troops and heavy weapons to Syria.

Russia has reportedly sent artillery units and tanks to an airport in Syria’s western province of Latakia, and also sent dozens of personnel and temporary housing for hundreds more.

According to a report published by the New York Times on Monday, Russia is using the airspace over Iran and Iraq to fly military equipment and personnel to a new air field in Syria.

At least seven giant Russian Antonov An-124 military transport aircrafts have taken off from a base in Russia during the past week to transport equipment to Syria, using Iranian and Iraqi air corridors, the Times reported, citing US officials.

American officials told the newspaper on Sunday that the destination of the Russian aircraft was an airfield in Latakia.

About 200 Russian marines and six Russian howitzers now guard the air base in Latakia, according to American intelligence.

On Wednesday, Kerry said that Russia had proposed opening a "military-to-military conversation" to ensure that Russian forces in Syria do not accidently clash with US troops fighting ISIL terrorists.