Cauacasian folk costumes were much in evidence at the ceremony

Dozens of tanks and hundreds of soldiers guarded the venue in the city of Gudermes against rebel attack.

Moscow says Mr Kadyrov's appointment is part of its plan to stabilise the troubled Russian republic.

Mr Kadyrov won a landslide victory in the earlier this month but the vote was rejected by separatists and dismissed by human rights groups as a farce.

The new president took an oath before some 250 people to "respect and defend the rights of my people".

Addressing the audience, he pledged to "do everything to unite our people and to provide them with safety".

Among those present was Russian President Vladimir Putin's chief of staff, Alexander Voloshin.

"There is great hope of life returning to normal... as a result of this election," he said before wishing the new president luck in his "difficult but necessary task".

Tight security

Security for the ceremony was so tight that the venue was announced only an hour before it began.

Gudermes, Chechnya's second city, never suffered the devastation endured by the regional capital, Grozny, and is located on a federal highway with easier access to other parts of Russia.

Many of the invitees had stayed overnight in the relative safety of Ingushetia.

Mr Kadyrov, a former rebel warlord who changed sides after Russian troops ejected the Chechnya's separatist government in 1999, swore allegiance to the new Chechen constitution adopted in a referendum in March this year.

A treaty to delineate powers between the region and the federal centre is due to be created, which Russian President Vladimir Putin says will give Chechnya "autonomy in the broadest sense of the word".