MOSCOW/WASHINGTON (Reuters) - 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.

FILE PHOTO: U.S. President Donald Trump and Russia's President Vladimir Putin are seen during the G20 leaders summit in Buenos Aires, Argentina November 30, 2018. REUTERS/Marcos Brindicci

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.

The two met briefly on the sidelines of major international events last December and November, after their summit in Helsinki last July when Trump refused to blame the Russian leader for meddling in the 2016 U.S. election, leading to an outcry in the United States.

Putin denies the allegations of Russian meddling.

Ushakov also said Putin planned to speak publicly a number of times during the G20 and would address “existing imbalances in the international financial system... (and) issues related to escalation of trade conflicts.”

“(Putin) Will share his views regarding the strengthening of the role of the World Trade Organization as a universal platform for resolving various disputes and for dialogue on global trade and economic issues,” Ushakov said.

China and the United States, the world’s two largest economies, are waging a costly trade war that has pressured financial markets and damaged the world economy.

Markets are focused on whether Trump and his Chinese counterpart Xi Jinping can narrow their differences when they sit down at the G20.