A UN engineer was among three people killed in a suspected suicide bomb attack on a popular internet café in Kabul Sunday.
Elsewhere in the country, two US marines were among 14 people killed in a five-hour gunbattle between US forces and insurgents in Laghman province, northeast of Jalalabad, near the border with Pakistan.
A military spokesman said a Marine unit had tracked the insurgents down and challenged them, leading to a firefight in which US airplanes were also involved.
In Kabul, reports said a man with two grenades strapped to his chest ran into the internet café and pulled the pins, causing an explosion which brought the roof down. The third victim, apart from the UN engineer from Myanmar and the bomber, was not immediately identified.
Condemning the bombing, UN secretary-general Kofi Annan warned that violence was rising in Afghanistan, where about 15,000 US troops are still battling remnants of the Taliban while searching for al Qaeda leader Osama bin Laden and his followers.
This excludes the 8,000 strong NATO-led International Security Assistance Force which supports the 'Afghan Transitional Authority in expanding its authority to the rest of the country.'
