Russian President Vladimir Putin and U.S. President Donald Trump will have an hour-long meeting on the sidelines of a G20 summit on June 28 in Osaka in Japan, a Kremlin aide said on Wednesday, in their first official encounter for almost a year.

The meeting will take place amid growing tension over Tehran. Trump threatened retaliatory attacks on Iran after blaming it for attacks on two oil tankers, while Iran has also shot down a U.S. surveillance drone.

Tehran has denied responsibility for the tanker attacks and has said the U.S. drone was flying in Iranian airspace.

Arm control treaties, which both Putin and Trump threatened to quit, will also be discussed by the two, according to the Kremlin fact sheet prepared for the meeting.

The Kremlin aide, Yuri Ushakov, said the leaders will also likely discuss “issues of strategic stability, numerous regional conflicts”, including Syria, Venezuela, and Iran.

Washington has not confirmed so far the date for the meeting. “It’s not a formal summit, but it is expected to be a conversation that will focus primarily on regional security issues, including Iran, Ukraine, Syria, the Middle East,” a U.S. senior administration official said. “They should also touch on arms control issues and on improving the bilateral relationship.”

Trump said last week he planned to meet Putin at the G20 summit in Japan, as reported by Reuters.