CHAPARHAR, Afghanistan -- A suicide car bomb attack has killed five civilians and a policeman at a checkpoint in the eastern Afghan province of Nangarhar, while a separate attack killed two civilians in Khost, officials said.
Violence is at its highest levels since U.S.-led forces toppled the Taliban in 2001, with attacks spreading from the south and east to the outskirts of Kabul, forcing Washington to consider new policy options including a counter-insurgency push.
The bomber, who was targeting a foreign forces convoy in Chaparhar district, was identified and fired on by the soldiers, district governor Hasan Khan told Reuters.
But the bomber managed to turn his car around and detonate his explosives at a nearby police checkpoint, he said.
"The bomber killed one policeman and five civilians, including three children, who were sitting on a passing tractor," Khan said. Five police were wounded in the attack, he said.
The NATO-led International Security Assistance Force (ISAF) confirmed, in a statement, there had been an attack on a temporary police checkpoint and said its soldiers provided immediate medical attention to the victims.
There were no ISAF casualties caused by the incident, he said.
The provincial governor, Gul Agha Sherzai, said earlier the bomber had been targeting an Afghan police convoy.
In a separate incident, a roadside bomb struck a passing car in the southeastern province of Khost, near a Muslim shrine where hundreds of people were gathering to celebrate the Afghan New Year, the provincial police chief told Reuters.
Two civilians were killed and four wounded in the blast, said police chief Abdul Qayum Baqizoy. The Taliban claimed responsibility for the Khost attack but told Reuters those who were killed were border police.
In another incident, a soldier from the NATO-led force was killed in a "hostile incident" in the south of the country on March 20, the alliance said in a statement. He was the fifth foreign soldier to die in two days.
Insurgents often target Afghan and foreign forces with suicide and roadside bomb attacks in an attempt to weaken the Afghan government and drive some 70,000 international soldiers from the country.
The United States is sending up to 17,000 more soldiers to Afghanistan over the coming months to help tackle the insurgency and provide security for the presidential election in August.
On March 21, the U.S. special representative for Afghanistan and Pakistan, Richard Holbrooke, told a security conference in Brussels that plans to boost the Afghan police force from 78,000 to 82,000 over the next three to four years were now regarded as too little.
"The police aren't very good right now. We know they are the weak link in the security chain," Holbrooke said. "So we are looking in conjunction with our allies and friends in the Afghan government at a very significant increase."