The Russian republic of Chechnya has sworn in a former rebel as president.

30-year-old Ramzan Kadyrov formally assumed office Thursday at a ceremony in Gudermes east of the capital, Grozny, where he called for a peaceful Chechnya.

He was nominated early last month by Russian President Putin and approved by the Chechen parliament a day later.

Ramzan Kadyrov is the son of Chechnya's first president Akhmad Kadyrov, who was assassinated in 2004. On Wednesday, Kadyrov announced that Russian forces had killed a senior rebel commander suspected of involvement in the assassination.

Originally a rebel like his father, Kadyrov became a Moscow ally, and his militia has helped federal troops hunt down most of the remaining insurgent leaders.

Human rights groups accuse Kadyrov of direct involvement in torture and disappearances, as well as the murder last October of a prominent Russian journalist Anna Politkovskaya - charges that Kadyrov denies.

Kadyrov's supporters credit him with restoring order after two wars between federal troops and rebel separatists.

Some information for this report was provided by AFP, AP and Reuters.