HELSINKI: The United Nations Security Council alone can authorise the use of force against Syria, Russian Foreign Minister Sergei Lavrov said on Monday, warning against what he called imposing "democracy by bombs".

Lavrov's warning against intervention comes as Syria's 17-month uprising against President Bashar al-Assad grinds on with no sign of a ceasefire and as the United States and others consider what further steps they can take to end the bloodshed.

"We find it appropriate to defend the U.N. Charter that states the use of force can be only be decided by the Security Council," Lavrov said in a speech in Helsinki, where he was meeting Finnish government leaders.

"Syria's situation is important and causing worry not only because of the bloodshed but also because the outcome of this drama will impact the way conflicts will be resolved; either following the U.N. Charter, or democracy by bombs, will win."

Russia has consistently defended Assad at the United Nations, blocking sanctions against him and ruling out the use of outside force to end the conflict. It has also supplied his government with arms, while complaining that Syrian rebels are receiving large amounts of Western-made arms.

Lavrov has said Moscow would not approve any political transition that was forced on Syria.

U.N. military observers left Damascus on Monday after a four-month mission.

At least 18,000 people have now been killed in Syria since the anti-Assad revolt began, and at least 170,000 people have fled the country, according to the United Nations. AGENCIES