In a tough worded address to top officials, President Vladimir Putin called on the US to immediately stop the war in Iraq, criticizing the war a "big political mistake" that threatens international security and could cause a humanitarian catastrophe.

The military action is being carried out despite international opposition and in violation of international law and the UN Charter, Putin stressed.

The president said there was no need to launch military action against Iraq, as the country, weakened by more than a decade of UN sanctions, posed no threat to its neighbors and other countries or regions of the world when the operation began.

Putin also called for returning the Iraq issue to the framework of the United Nations, which he stressed should play central role when resolving world crises.

"If we allow international law to be replaced by the right of might, under which the strong is always right and has the right to choose the means to achieve his goals without limits, then one of the main principles of international law, the principle of the inviolability of the sovereignty of states, will be thrown into question," he said.

The United States launched air strikes against Iraq hours after the expiry of a US ultimatum demanding Iraqi President Saddam Hussein leave Iraq within 48 hours or face war.

Russia, a veto-wielding permanent member of the UN Security Council, has repeatedly voiced opposition to military operations against Iraq, and called for further weapons inspections in the country.

Earlier Thursday, Russian Prime Minister Mikhail Kasyanov expressed regret over the US military operation in Iraq, while pledging to help the Iraqi refugee forced to leave home due to the war.

"The Russian administration expresses regret that the Iraqi crisis is being resolved by military means without permission from the UN Security Council -- that is, the international security system," said Kasyanov when opening a government session.

He said Russian relief officials would soon be sent to nations bordering Iraq to provide humanitarian aid to Iraqis.

Deputy Emergency Situations Minister Yuri Brazhnikov said Russia would aid Iran in receiving refugees and would help equip Iranian-built camps. He said the ministry would soon send two Il-76 cargo planes to the western Iranian city of Kermanshah with tents, beds, blankets, stoves and other necessities, the Interfax news agency reported.

The State Duma, lower house of the parliament, on the same day gave preliminary approval to a draft resolution that appeals for a special UN General Assembly session on Iraq.

The resolution called on UN Secretary General Kofi Annan and the UN Security Council "to urgently assess the military operation launched by the US and its allies and do everything to settle the Iraq crisis peacefully."

At the same time, the Duma has rejected a draft by the leftist factions, which called for abandoning the UN sanctions regime against Iraq, providing weapons to Baghdad and suspending consideration of the ratification of a key US-Russian arms treaty.

On Thursday, hundreds of Communists, nationalists and others held an anti-war protest across from the US Embassy in Moscow.

The Interfax quoted an Interior Ministry official as saying that Russia had beefed up police stationed outside the embassies of the United States, Britain, Spain, Turkey, Kuwait and other nations. Security has also been increased at nuclear power plants, industrial plants dealing with toxic materials and other sites "incase of an increased terrorist threat," the news agency said.

However, Foreign Minister Igor Ivanov said that Moscow and Washington would remain partners despite Russia's "deep regrets" over the US-led war in Iraq.

Russia deeply regrets the war launched by the United States, but the two nations would "remain partners, not opponents, " Ivanov was cited by the Interfax news agency.

(Xinhua News Agency March 21, 2003)