Police killed 11 suspected Taliban insurgents in two separate operations in southern Afghanistan, an official said Tuesday, a day after three bombings killed 20 people, including four Canadian soldiers.

The suspected Taliban were killed in clashes in Helmand province, said Ghulam Rasool, a regional police chief. Four others were injured, he said.

Police recovered the militants' bodies and their weapons after the operations late Monday and early Tuesday, he said. There were no police casualties.

President Hamid Karzai condemned Monday's triple bombings as "heinous acts of terrorism (which) are against the values of Islam and humanity."

The deadliest of the attacks, in the usually calm western city of Herat, killed 12 people and wounded 17 including the deputy police chief, officials said. Initially, officials said it was a suicide attack by a militant strapped with explosives and riding a motorbike.

But Karzai, speaking Monday in New York where he was attending the U.N. General Assembly, said it was not a suicide attack. He did not elaborate.

"It was not a suicide attack as I know now," he said.

CountryWatch: Afghanistan

A suicide car bombing in the capital, Kabul, killed at least four policemen and wounded one officer and 10 civilians.

Afghanistan has been suffering the heaviest insurgent attacks since the Taliban was toppled in late 2001, and the bombings came a day after NATO ended a two-week offensive, Operation Medusa, against Taliban fighters in the south that the commander of NATO forces in the country, Lt. Gen. David Richards, called a "significant success."

"It does appear that they are resorting to these despicable tactics after the pressure we have them under in their strongholds," a NATO spokesman, Maj. Luke Knittig, said in Kabul.

Operation Medusa centered on southern Kandahar province's Panjwayi district, where the first of Monday's bombings targeted a Canadian foot patrol delivering aid and reconstruction assistance, killing four soldiers and wounding an unspecified number of others, the Canadian military said. About 25 civilians were wounded in the blast, NATO said.

The district suffered heavy damage in the NATO offensive.

A purported Taliban spokesman, Qari Yousaf Ahmadi, claimed responsibility for the bombing in a telephone call to The Associated Press.

"Fifty to 60 soldiers were patrolling on the main street when a man on a bicycle stopped and blew himself up near the forces," said Fazel Mohammed, a farmer who lives near the blast site.

At least 36 Canadian soldiers have been killed in Afghanistan since 2002. Five died during Operation Medusa, in which NATO estimated it killed at least 510 insurgents with airstrikes and ground assaults.