Two hundred Mexican Navy marines stormed an upscale apartment complex and killed a reputed drug cartel chief in a two-hour gun battle, one of the biggest victories yet in President Felipe Calderon's drug war.

Arturo Beltran Leyva, the "boss of bosses", and six members of his cartel died in the shoot-out Wednesday in Cuernavaca, just south of Mexico City, according to a navy statement yesterday.

The body of one cartel member was found on the ground outside the third-floor apartment after he apparently committed suicide during the shoot-out. Cartel gunmen hurled grenades that killed one marine and wounded two others, one of whom is in serious condition, the navy said. Two women and one man were detained during the raid, and five assault weapons were seized.

An Associated Press reporter at the scene heard at least 10 explosions during the firefight, which residents said lasted at least 90 minutes. Witnesses said the raid began when marines rappelled down ropes on to the roofs of some of the apartment buildings at dusk.

Reporters were briefly allowed inside the apartment where Beltran Leyva's body still lay early yesterday, his skull and one arm were mangled by bullet wounds, and in one hand he clutched a large gold-coloured medallion.