A Free Syrian Army fighter carries a weapon as he walks towards his position on the front line against Assad forces in a Damascus suburb, Syria, in this July 27, 2015 file photo.

The United States and Russian militaries renewed high-level contacts on Friday to discuss their roles in the conflict in Syria, Pentagon spokesman Peter Cook said as Secretary of State John Kerry arrived in Britain to discuss the Syrian crisis with Russia.

Cook said U.S. Secretary of Defense Ash Carter and Russia’s Defense Minister Sergei Shoigu spoke by telephone. He added: “The secretary and the minister talked about areas where the United States and Russia’s perspectives overlap and areas of divergence.”

“They agreed to further discuss mechanisms for deconfliction in Syria and the counter-ISIL campaign,” he added, referring to the Islamic State of Iraq and Syria (ISIS) militant group.

In military terms, “deconfliction” means rival armies will talk to one another to avoid accidental encounters between their forces.

Kerry in London

Meanwhile, Kerry said during a visit to London on Friday that Washington hopes that “military-to-military” discussions with Russia on the conflict in Syria will begin very 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 after talks with UAE Foreign Minister Abdullah bin Zayed.

“Obviously our focus remains on destroying ISIL (Islamic State of Iraq and Syria) and also on a political settlement with respect to Syria,” he added.

The White House said Thursday it was open to limited talks with Moscow following what Washington believes is the deployment of Russian troops and heavy weapons to war-torn Syria.

White House spokesman Josh Earnest said President Barack Obama’s administration was willing to hold “tactical, practical discussions” on operations in Syria and the fight against the Islamic State group.

In a related story, Kerry met briefly with Israeli opposition leader Isaac Herzog in London where they discussed crises in the Middle East, the Iran nuclear agreement, and current tensions in Jerusalem.