Russia has slammed the holding of a U.S.-led counterterrorism summit of some 100 leaders on the sidelines of the UN General Assembly in New York.
Russia's ambassador to the UN, Vitaly Churkin, said on September 29 that the "initiative seriously undermines UN efforts."
"We believe everything must take place in an orderly fashion, in the UN framework, without pulling up the blanket and performing the UN role," he told reporters.
U.S. President Barack Obama is chairing the UN gathering on September 29.
Obama is seeking support for the fight against the Islamic State extremist group.
Russian President Vladimir Putin met Obama on the sidelines of the UN General Assembly on September 28 to discuss the Syrian war.
Russia is attending the meeting on September 29.
Russia, which is president of the UN Security Council for the month, will chair its own meeting on September 30 on countering extremism.
Based on reporting by BBC and Interfax