The son of the slain pro-Moscow Chechen president Akhmad Kadyrov was appointed deputy leader of the troubled region yesterday as thousands of mourners bid his father farewell at his Muslim funeral.

The appointment of Ramzan Kadyrov, a boxer, is controversial andlikely to stoke speculation that the Kremlin is lining him up to succeed his father.

Ramzan, 27, gained a fearsome reputation as the head of his father's 1,500-strong security unit and is accused of presiding over the abduction and torture of hundreds of Chechen civilians. The Moscow-backed administration's statistics show that last year alone 477 Chechens "disappeared", often in the middle of the night.

A tearful Ramzan, who denies all such accusations, appeared on Russian television with a sombre-faced President Vladimir Putin just two hours after his father was blown up in a sports stadium on Monday. His elevation to the deputy leadership of the republic was sanctioned by the Prime Minister, Sergey Abramov, Chechnya's acting president.

Ramzan's face was prominent on Russian television again yesterday as he and his brother Zelimkhan helped to carry their father's sheepskin-covered body to its final resting place in his home village of Tsentoroi, 30 miles south-east of Grozny, the Chechen capital.

Thousands of Chechens paid their last respects to the mufti turned politician weeping and chanting Muslim prayers before lowering his body into the earth. Yesterday was the first of three days of official mourning.

Investigators appear to have made little progress in tracking Mr Kadyrov's murderers, but believe that the bomb which killed him was planted long ago on the off-chance that he or one of his senior lieutenants might appear in the sports stadium.

Mr Kadyrov's colleagues say he had not intended to be at the stadium for the Second World War victory parade but made a last-minute decision to attend.

The authorities say the explosion was caused by two artillery shells which were detonated under the stadium's VIP stand either by remote control or by a timer device. One of the shells failed to explode.

The senior federal prosecutor in southern Russia, Sergei Fridinsky, suggested that whoever was behind the explosion had help from someone with access to the stadium, saying in televised comments that the level of security meant "an outsider could not have come and set off an explosive device".

The official death toll ranges from six to 30, with the authorities saying that it is too early to give a precise figure. Among the dead were Khusein Isayev, the head of Chechnya's State Council, and a photographer for the Reuters news agency, Adlan Khasanov, who was taking pictures near Mr Kadyrov when the explosion occurred.

Twenty-one people were in hospital yesterday, including General Valery Baranov, Russia's senior military figure in Chechnya, who is in a stable condition, having had a leg amputated.

The Russian government is convinced that the attack was the work of Chechen separatists who have been waging an armed struggle for independence from Russia for much of the past decade.

The separatist leader Aslan Maskhadov has denied involvement in the attack, claiming yesterday that the assassination was the work of the Russian security service "to liquidate the puppet government". He alleges that Mr Kadyrov had served his purpose and Moscow wanted fresh blood.