Russia appealed for restraint Thursday as concerns mount over a potential US strike on Iran, even while Moscow and Tehran carry out joint naval exercises that the Kremlin says were scheduled in advance and should not be seen as provocative.

Iran has become one of Russia’s closest partners since the start of Moscow’s campaign in Ukraine.

The United States has significantly increased its military presence in the Middle East, and President Donald Trump has pressed Iran to reach an agreement with Washington, implying that military force could follow if negotiations collapse.

Moscow and Iran are also conducting naval maneuvers in the Sea of Oman Thursday.

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

“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 adds.

Moscow says that “political and diplomatic means to be given absolute priority in resolving various issues,” according to Peskov.

Several nations have urged their citizens to leave Iran, warning of the possibility of a military clash.

“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 says.