Several councillors were among the dead
A suicide blast in the Sri Lankan town of Anuradhapura has killed at least 27 people, including a former senior general, according to the army.
Maj Gen Janaka Perera, a controversial commander in the Jaffna peninsula in the 1990s, died alongside his wife.
More than 80 people were injured when a suicide bomber blew himself up inside the United National Party office near a bus depot, officials said.
They blamed the attack on separatist Tamil Tiger rebels.
Gen Perera was the provincial leader of the United National Party (UNP), the country's main opposition party, and a critic of President Mahinda Rajapaksa's government.
The UNP has accused the government of ignoring repeated requests for a stronger security detail for Gen Perera.
"The government must take full responsibility," said party offical Tissa Attanayake. "They did not give him adequate security for political reasons."
Three opposition provincial councillors are among the dead, a military spokesman said.
The attack comes as the Sri Lankan military continues to close in on the Tamil Tigers' northern stronghold of Kilinochchi.
The head of the army says his troops are within 2km (1.25 miles) of the Tigers' administrative headquarters in the town.
Journalists are not allowed access to the fighting to verify such claims.
However, the progress of the government offensive has raised fears that the Tigers will step up suicide attacks.
Analysts warn that the Tigers' ability to carry out such attacks cannot be ignored.
The aftermath of the blast in Anuradhapura
Gen Perera was one of Sri Lanka's most prominent army officers and held the command of government forces in the Jaffna peninsula, a Tiger stronghold, in the mid-1990s.
The Tamil community accused him of being responsible for hundreds of deaths and the torture of Tamils in the region during the period.
The human rights group Amnesty International raised similar concerns.
After retiring from the army, Gen Perera served as Sri Lanka's high commissioner to Australia and ambassador to Indonesia.
His appointment as the envoy to Australia in June 2001 sparked protest demonstrations in Sydney.
More than 300 Tamils protested outside the Australian parliament accusing Gen Perera of "war crimes".
The Tamil Tiger rebels have been fighting for a separate homeland for a quarter of a century and about 70,000 people have been killed in the violence.