At least six people have died and more than 90 others have been wounded in a fire on a navy ship docked in the southern Pakistani city of Karachi. A "fireball" engulfed the logistics vessel during routine maintenance and cleaning work, a navy spokesman said.

He said that the wounded - some of whom are reported to have been severely burnt in the restricted dockyard area - were being treated in a navy hospital.

Officials refuse to speculate on what could have been the cause of the fire.

"There was a huge fireball," navy spokesman Salman Ali told the Reuters news agency. "Thank God, now the fire has been extinguished."

Mr Ali said that the blaze broke out during maintenance work on PNS Moawin, an auxiliary vessel that serves as one of two fleet tankers. It is reported to be badly damaged.