KABUL, Afghanistan – A U.S. customs employee and two British soldiers have died in insurgent attacks in southern Afghanistan where violence persists despite a winter lull in fighting across the nation.

A suicide bomber killed a retired U.S. Customs and Border Protection officer and wounded three other American customs workers Monday in Kandahar, which remains a hotbed of Taliban activity despite an influx of U.S. troops over the past year,

U.S. 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 U.S. government for 30 years, died in the blast at the Inland Customs Warehouse in Kandahar.

Afghan police said the suicide bomber detonated his 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.

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

The British Ministry of Defense said the two soldiers from a parachute regiment were shot and killed while on patrol in Nad Ali district of Helmand province Wednesday morning. Ten NATO service members have been killed so far this month.

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.

Separately, Britain's ambassador to Iran has been picked as NATO's new senior civilian representative in Afghanistan.

NATO Secretary-General Anders Fogh Rasmussen announced Wednesday that Simon Gass will succeed Mark Sedwill in the position.

NATO's civilian representative works to make sure that governance and development work is coordinated with the coalition's military effort.

Gass, who has been the British ambassador to Iran since early 2009, will formally accept the appointment when NATO foreign ministers meet in April in Berlin.

"Ambassador Gass is a highly qualified diplomat who will bring a regional perspective to this important post," Rasmussen said. "He knows how important the civilian and political aspects of NATO's engagement in Afghanistan are, as Afghans start taking the lead for their own security in the first half of this year."