KABUL A roadside bomb exploded under a bus in Afghanistan on Monday killing nine civilians, police said, two days after 11 children and a woman were killed during a NATO attack on militants in another part of the country.
Also on the weekend, a car bomb killed five Americans, including three U.S. soldiers, a young diplomat and a U.S. Defense Department contractor, in the southern province of Zabul.
Violence traditionally picks up in the Afghan spring as snow melts in mountain passes. This year, a major question will be whether Afghan forces can deal with a surge of attacks as most foreign forces prepare to leave by the end of next year.
Twenty-two people were wounded in the Monday blast in Wardak province, southwest of the capital, Kabul, said the provincial police chief's spokesman, Abdul Wali.
The Interior Ministry said the bomb had been planted by the Taliban but a spokesman for the insurgents, Zabihullah Mujahid, said the bomb was not theirs.
"We strongly reject involvement in this attack," he said.
The bus had been travelling from the southern province of Ghazni to Kabul, Wali said.
The NATO-led International Security Assistance Force has not accepted responsibility for the deaths of the 11 children and the woman in Saturday's fighting in Kunar province, on the Pakistani border, saying it remained unclear who caused the deaths.
In one of the worst attacks in the war, Taliban fighters raided a provincial court compound in the western province of Farah last week and killed 44 people, most of them civilians.
(Reporting by Mirwais Harooni; Editing by Dylan Welch and Robert Birsel)