US soldiers walk towards the scene of an explosion in Kandahar, south of Kabul, February 7, 2011. — Photo by AP

KABUL: Insurgents killed two members of Nato's mission to Afghanistan in the south of the country Wednesday, the multinational force said.

Nato didn't release the names of the service members killed or say exactly where the attack took place. Ten service members with the international coalition have died so far this month.

A suicide bombing earlier this week in the southern province of Kandahar, which remains a hotbed of Taliban activity despite an influx of US troops over the past year, killed a retired US Customs and Border Protection officer and wounded three other US customs workers.

US Homeland Security Secretary Janet Napolitano said in a statement released late Tuesday in Washington that David Hillman, a retired customs officer who had worked for the US government for 30 years, died in the blast Monday at the Inland Customs Warehouse in Kandahar.

Afghan police said the suicide bomber detonated a cache of explosives inside the city's customs house compound during a visit by Nato forces.

The Taliban in Kandahar are attacking officials and others who support pro-government forces. Earlier this month, a suicide bomber killed the province's deputy governor. Afghan officials have been targeted elsewhere too.

In the northern Balkh province, a roadside bomb exploded and killed the director of criminal investigations in the province's Chimtal district. Provincial police spokesman Sher Jan Durani said four bodyguards were also wounded when the bomb struck the vehicle carrying the official, Noor Ahmad.

Last year was the deadliest of the nearly decade-long war for international troops, with more than 700 killed, compared to just more than 500 in 2009.