Iranian President Ebrahim Raisi told Russian President Vladimir Putin on Thursday that NATO's expansion was a "serious threat" to the region's security and stability, Reuters reports.
"NATO's expansion eastward creates tension and is a serious threat to the stability and security of independent states in various areas," Raisi was quoted as saying following Russia's military attack on Ukraine.
"I hope what is happening will benefit peoples and the entire region," added the Iranian President.
Earlier this week, Iran sided with Russia amid tensions with Ukraine, blaming the United States and NATO for the situation.
"The Islamic Republic of Iran calls on all parties to exercise restraint and avoid any action that could aggravate tensions," said a foreign ministry statement quoted by AFP.
Ministry spokesman Said Khatibzadeh added that "unfortunately, the interventions and provocative actions of NATO and mainly the US have complicated the situation in the region.
"We are following the issues related to this country with sensitivity," he added. The statement came a day after Putin recognized two separatist regions in Ukraine as independent and later announced he would deploy "peacekeeping" forces there.
Early Thursday morning, Putin launched an invasion of Ukraine, claiming that the clashes between Russian forces and Ukrainian forces were inevitable.