(Adds bomb detail, quote, paragraphs 4, 8) By Ranga Sirilal COLOMBO, Jan 5 (Reuters) - Suspected Tamil Tiger rebels set off a bomb in a bus in western Sri Lanka on Friday, killing at least five people and wounding 30, the military said, as fighting raged in the north and east of the island. Around 80 people were aboard the bus when the blast occurred in the town of Nittambuwa, 36 km (20 miles) north of Colombo, during evening rush hour. "It was a bomb inside the bus, very powerful, the bus caught fire," said military spokesman Brigadier Prasad Samarasinghe. "The Tigers are targeting civilians." He said the bomb was place beneath a passenger seat. There was no immediate comment from the Liberation Tigers of Tamil Eelam, who want to carve out a separate homeland for minority Tamils in the east and north of the island. Samarasinghe said at least five people were killed and he expected the death toll to rise further. "There are at least 30 injured, 10 of them serious, the number may go up." The blast in the relatively peaceful west took place at a time when the Sri Lankan military has launched air and artillery attacks on the LTTE in the north and the east of the island. "The LTTE is carrying out terror attacks against civilians because it is unable to bear the continuous defeats at the hands of the security forces," defence spokesman Kehelia Rambukwela said. More than 3,000 people were killed in suicide bombings, aerial and naval raids and clashes last year despite a 2002 ceasefire that international monitors say now exists only on paper. A mine explosion earlier in the day in the rebel-controlled northern region killed two government agriculture officials, the Tigers said, blaming the blast on government forces. The Tigers said a Sri Lankan army group had crossed into the rebel-controlled Nedunkeni area, apparently to target rebels but hit the government officials by mistake. The military denied any involvement. Sri Lankan government planes pressed on with attacks on rebel bases for a fourth consecutive day on Friday. The military said a Sea Tiger base in the northern rebel-controlled Mullaittivu area was destroyed. It did not give any details on casualties. Independent confirmation of the fighting is not possible, and both sides often exaggerate rival losses while downplaying their own. Violence between the military and the LTTE has escalated in recent weeks, with the government vowing to dislodge the rebels from their strongholds in the east. (Writing by Sanjeev Miglani, editing by Stephen Weeks; Reuters Mesaging:sanjeev.miglani.reuters.com@reuters.net))
