Russia and Iran both condemned the U.S. and U.K. on Friday for military strikes on Yemen, as Moscow called for an urgent U.N. meeting to address the issue.
Moscow said the airstrikes amounted to an irresponsible adventure that risked sowing chaos across the entire Middle East.
Early Friday, the United States and Britain launched strikes from the air and sea against Houthi military targets in Yemen in response to the Iran-backed movement's attacks on ships in the Red Sea, a dramatic regional widening of Israel's war in Gaza.
"We strongly condemn these irresponsible actions by the United States and its allies," Maria Zakharova, Russia's foreign ministry spokesperson, told reporters.
"A large-scale military escalation in the Red Sea region could strike out the positive trends that have emerged recently in the Yemeni settlement process, as well as provoke a destabilization of the situation throughout the Middle East."
Russia, which has been criticized for what the West says is an illegal war in Ukraine, said the attack on Yemen took place without any mandate from the United Nations and was thus an illegal "adventure" by the United States and its allies.
Russia said it shared the concerns of Saudi Arabia and others in the region over the strikes. Riyadh called for restraint and "avoiding escalation" after the strikes and said it was monitoring the situation with great concern.
"We share the concerns expressed by our regional partners, in particular from Saudi Arabia," Zakharova said.
Iran has also strongly condemned the U.S.-led strikes as illegal and escalatory.
The attack was a clear violation of Yemen's sovereignty and territorial integrity and a breach of international law, the state news agency IRNA quoted Foreign Ministry spokesperson Nasser Kanaani as saying.
"These indiscriminate attacks will not lead to any result except fueling insecurity and instability in the region."
A spokesperson for Yemen's Houthis said there was no justification for the U.S.-British attack and said the group will continue targeting ships heading towards Israel.
Meanwhile, China called on Friday for all sides to prevent the Yemen conflict from expanding.
"China is concerned about the escalation of tensions in the Red Sea," foreign ministry spokesperson Mao Ning said.
"We urge the relevant parties to keep calm and exercise restraint, to prevent the conflict from expanding," she added.
Beijing stressed that the "Red Sea region is an important passage for international logistics and the energy trade."
"We hope that the relevant parties can all play a constructive and responsible role in protecting the regional security and stability of the Red Sea, in line with the international community's shared interests," Mao said.
China, she added, urged "all parties to jointly maintain the security of international waterways and avoid harassing civilian vessels, as this is detrimental to the global economy and trade."
The U.S., on the other hand, said Australia, Bahrain, Canada and the Netherlands supported the operation.
It sought to present the strikes as part of an international effort to restore the free flow of trade in a key route between Europe and Asia that accounts for about 15% of the world's shipping traffic.
