A homicide bomber who hugged a former army general before detonating his explosive-laden vest killed 27 people gathered in a crowded opposition party office in northern Sri Lanka on Monday.

The attack by a suspected rebel came as government troops, in the midst of an offensive against the Tamil Tigers de facto state in the north, closed in on the rebels' administrative capital of Kilinochchi, military spokesman Brig. Udaya Nanayakkara said.

The bomber blew himself up as officials from the opposition United National Party gathered to open a new office in the northern town of Anuradhapura. The blast killed retired Maj. Gen. Janaka Perera, his wife and 25 others, including a television journalist covering the event. It wounded at least 80 people, Nanayakkara said.

Wearing a hidden explosives vest, the bomber "embraced the former commander" before detonating, the rebel-affiliated TamilNet Web site reported, noting that Perera played a key role in evicting minority Tamils from northeastern villages in 1984 to settle ethnic Sinhalese there.

Rebel officials could not be reached for comment on the attack because communication lines have been cut to guerrilla-dominated areas in the north.

The attack underlined analysts' warnings that a conventional victory on the battlefield might drive the guerillas to focus increasingly on homicide bombings and other attacks on civilians.

"Whether the war is won or not, these kind of guerrilla attacks and sabotage will go on. You have to expect it," said former army commander Gen. Jerry de Silva.

The rebels, listed as a terror group in the United States and the European Union, are said to have carried out more than 240 homicide attacks against military, political and economic targets.

Diplomats have long called for a political solution to the quarter-century ethnic conflict, in which the Tamil Tigers are fighting to create an independent homeland for minority Tamils, who faced years of marginalization at the hands of governments controlled by the Sinhalese majority. More than 70,000 people have been killed in the violence.

The United States condemned Monday's attack, but encouraged the government to find a political solution. "Only a political solution, not further violence, can provide a way forward to ending the country's deadly conflict," the U.S. Embassy said in a statement.

Indian officials told a Sri Lankan diplomat on Monday to express "grave concern and unhappiness" about growing civilian casualties in the conflict, and called for greater restraint from army.

Meanwhile, fighting continued Sunday along the northern front lines separating the government territory and the rebels' de facto capital, killing 14 rebels and one soldier, a military statement said.