Russia urged restraint on Thursday amid escalating tensions over a potential U.S. attack on Iran, while Moscow and Tehran conducted naval drills, which the Kremlin stated were pre-scheduled and should not be seen as a cause for concern.

The United States has massively built up its forces in the Middle East and President Donald Trump has warned Iran to make a deal with Washington, hinting at military action, The Caspian Post reports, citing foreign media.

Moscow and Iran were holding navy drills in the Sea of Oman Thursday.

“These are planned exercises and they are agreed upon in advance,” Kremlin spokesman Dmitry Peskov said.

“Russia continues to develop relations with Iran and in doing so, we call on our Iranian friends and all parties in the region to exercise restraint and prudence” he added.

Moscow was calling for “political and diplomatic means to be given absolute priority in resolving various issues”, Peskov said.

Some countries have urged their citizens to leave Iran, citing the threat of a military conflict.

“We are currently witnessing an unprecedented escalation of tension in the region, but we still hope that political and diplomatic means and negotiations will continue to prevail in the search for a settlement,” Peskov said.

Iran and the US held another round of talks this week in Geneva.

Iran has become one of Russia’s closest allies during Moscow’s Ukraine offensive.