GROZNY, Russia, May 25 (AFP) - A bomb exploded in the centre of Grozny Tuesday, killing four bodyguards accompanying the mufti of Chechnya, security sources said. Akhmad-Khadja Kadyrov, the mainly Moslem republic's mufti, escaped unhurt in the blast which destroyed his car mid-afternoon some 300 metres (yards) from the republic's interior ministry, Djamal Eskayev, the officer in charge of investigations into the blast, said. He added that the explosion, of a force equal to 1.5 kilos (3.3 pounds) of TNT, and an attempt on the life of an adviser to President Aslan Maskhadov on Sunday were "two links of the same chain." Danilbek Tamakayev, the adviser, was seriously injured by Sunday's explosion which occurred when he was driving west of the Chechen capital President Maskhadov is at loggerheads with the former nationalist leaders of the 1994-1996 war against Russian rule who consider him too favourable towards Moscow.  