MANILA, Dec 29 - A bombing wounded 33 people during an amateur boxing match in a central Philippines province, the government said on Thursday, the second attack on a public place by unknown perpetrators in less than a week. An 81-millimeter mortar round was detonated remotely by cellphone during the amateur bout outside a shopping mall in Leyte province late on Wednesday. Police said no suspects had been identified and no group had claimed responsibility. It followed a Christmas Eve grenade explosion outside a Catholic church that wounded 16 people on the southern island of Mindanao, a Muslim-dominated region where a long-running insurgency is being fought. Police said there was no indication the two attacks were linked.