Violence in Sri Lanka left at least 50 people dead Monday, most of them schoolgirls killed in what Tamil Tiger rebels say was a government air raid on a children's home in rebel territory.

The government denied attacking a children's home, insisting it struck a rebel base.

CountryWatch: Sri Lanka

The violence appeared to dash what little hope was left for a quick end to fighting that has steadily worsened over the past four weeks, undermining an already shaky cease-fire.

The 2002 truce was intended to halt more than two decades of bloodshed between the government, dominated by Sri Lanka's 14 million Sinhalese, and the rebels, who have been fighting since 1983 for an independent homeland for the country's 3.2 million Tamils.

The cease-fire remains officially in effect, but months of shootings and bombings already had left it in tatters before the latest round of clashes.

In fighting Monday, Sri Lankan air force jets bombed the northeastern Mullaitivu district, deep inside rebel territory, hitting a children's home and killing 43 schoolgirls who were there taking a first aid course, the pro-rebel TamilNet Web site reported.

Another 60 girls were wounded in the morning air raid on the home, TamilNet said, citing officials from the Liberation Tigers of Tamil Eelam, as the rebels are formally known.

But Air Force spokesman Group Capt. Ajantha Silva said the government has proof the facility was a rebel base.

Hours later in Colombo, an auto rickshaw packed with explosives blew up as a car carrying Pakistan's high commissioner, Basir Ali Mohmand, passed along a crowded road. At least seven people were killed, including four army commandoes guarding the envoy, said defense spokesman Keheliya Rambukwella. Another 10 people were wounded.

The diplomat, who was believed to be the target of the blast, escaped unhurt, he said, blaming the Tigers for the attack. Pakistan is a major supplier of arms to Sri Lanka's military.

Tamil Tiger officials were not immediately available to comment, although in recent months they have often kept quiet after such attacks, neither confirming nor denying involvement.

Pakistani officials said it was the first attack on any of their diplomats in Sri Lanka.

A day earlier, at least 15 people died in fighting around the St. Philip Neri Church in Allaiiddy, a predominantly Tamil village located on an island just west of the Jaffna Peninsula. The island, like the peninsula, is held by the government.

TamilNet said the dead were civilians killed when government artillery and rocket fire hit the church, where they were sheltering. While TamilNet stopped short of saying government forces intentionally targeted the church, it said no help was sent to the wounded for hours after the attack.

But the military countered that guerrillas in the church fired on troops as they tried to enter the building, and that the civilians were killed in the fighting.

The latest round of fighting began in late July over a rebel-controlled water supply near the eastern port of Trincomalee, and had in recent days spread to other parts of the east and the Jaffna Peninsula, the scene of intense fighting during Sri Lanka's two decade-long civil war.

Attempts to restart peace talks and end the fighting have so far failed. The rebels on Saturday said the clashes made a government offer to resume peace talks impossible.

"The Sri Lankan government's offensive attacks make peace talks and the implementation of the cease-fire agreement impossible," Seevarathnam Puleedevan, a senior rebel official, told The Associated Press in a telephone interview from rebel territory.

Government and rebel estimates of the death toll in the fighting since July vary wildly, but scores have been killed, including 17 Sri Lankans working for the Paris-based aid group Action Against Hunger. All but one of the aid workers was Tamil.