Vladimir Putin, the Russian president, has harshly criticised the US for what he said was an attempt to force its will on the rest of the world.
"What is a unipolar world? No matter how we beautify this term it means one single centre of power, one single centre of force and one single master," Putin said to an annual gathering of top security and defence officials in Munich, Germany, on Saturday.
"It has nothing in common with democracy because that is the opinion of the majority taking into account the minority opinion," Putin said.
"People are always teaching us democracy but the people who teach us democracy don't want to learn it themselves."
Responding later on Saturday, the US rejected the Russian leader's remarks.
Gordon Johndroe, press secretary for the White House National Security Council, said: "We are surprised and disappointed with President Putin's comments. His accusations are wrong."
'World less safe'
Putin said that the US, above other western nations, had repeatedly overstepped its national borders in questions of international security, a policy that he said had not made the world safer.
On the contrary, the world had become less safe, he said.
Putin said: "Unilateral actions have not resolved conflicts but have made them worse.
"This is very dangerous. Nobody feels secure any more because nobody can hide behind international law."
He did not mention any specific conflicts, but he has been very critical of the US decision to invade Iraq in 2003.
Missile defence system
Putin also voiced concern about US plans to build a missile defence system in eastern Europe, probably Poland and the Czech Republic, and the expansion of Nato as possible challenges to Russia.
"The process of Nato expansion has nothing to do with modernisation of the alliance or with ensuring security in Europe," Putin said.
"On the contrary, it is a serious factor provoking reduction of mutual trust."
He also dismissed suggestions that the European Union and Nato had the right to intervene alone in crisis regions.
"The legitimate use of force can only be done by the United Nations, it cannot be replaced by EU or Nato," he said.
On the missile defence system, Putin said: "I don't want to accuse anyone of being aggressive" but suggested it would seriously change the balance of power and could provoke an unspecified response.
"That balance will be upset completely and one side will have a feeling of complete security and given a free hand in local, and probably in global, conflicts...," he said.
"We need to respond to this."