At least 14 people have been killed and dozens wounded after a suicide bomber blew himself up in a busy market in eastern Afghanistan.
The Taliban claimed credit for Sunday's bombing in Gardez which came a day after a suicide blast in the northern town of Kunduz killed 10 people, including three German soldiers.
Zabiullah Mujahid, a Taliban spokesman, said: "We claim responsibility for the attack. It was a suicide attack. Our Afghan mujahid carried it out."
But Hamid Karzai, the Afghan president, told Al Jazeera that the war on terror in his country was won long ago and the real problem was in Pakistan.
"The war against Taliban in Afghanistan was won in 2001," he said.
"We don't have same problem Pakistan is facing today. Look at the mosque in Islamabad. Look at incidents in Karachi, Peshawar, a week ago.
"The Taliban problem is indeed as much or more a problem in Pakistan as perhaps it is in Afghanistan."
Zemarai Bashary, an interior ministry spokesman, said about 40 people were either dead or wounded in the blast in a crowded market and bus stop in the centre of Gardez, capital of Paktia province and 100km south of the capital, Kabul.
Rahmatullah Rahmat, the governor of Paktia, said the bomber struck as a convoy of foreign forces was passing through the street market.
A spokesman for the US-led coalition said some of its soldiers were wounded, but had no more details.
The International Security Assistance Force, which leads thousands of foreign troops in Afghanistan, had initially said its troops were involved, but later said that report was wrong.
As details emerged about the blast, the governor of Ghazni province said Afghan and Nato forces killed about 30 Taliban fighters and arrested 12 others in Qara Bagh district on Saturday night.
Merajuddin Patan, the governor, told Reuters: "Unfortunately three police are missing and one is wounded."
The attack in Kunduz on Saturday was aimed at German soldiers who were shopping in a market. The Taliban claimed responsibility.
The Taliban says it will step up suicide attacks across the country to avenge the killing of Mullah Dadullah, its military commander, last week.