GROZNY, November 13 (RIA Novosti) - Some 20 militants were killed in a special operation on Friday, the president of the volatile North Caucasus republic of Chechnya said.

"Up to 20 militants were killed. Many bodies cannot be identified because of mutilation," said Ramzan Kadyrov, who commanded the special operation.

He said the bodies of ten militants had been recovered so far. The operation began with a helicopter attack and a battle followed. No Russian troops were killed.

Kadyrov said that Islam Uspakhadzhiyev, a close ally of warlord Doku Umarov, was identified among those killed. He added that Umarov himself could be among them.

"The search for militants will continue in the morning," said Kadyrov, who was recently promoted to major-general of police forces by Russian President Dmitry Medvedev.