Updated at 4:20 a.m. Eastern.
A roadside bombing killed four U.S. service members, the first American combat deaths of the year in Afghanistan, while a British soldier died during a foot patrol elsewhere in the volatile south of the country, officials said Monday.
A statement from NATO's International Security Assistance Force said the explosion that killed the U.S. service members took place Sunday in the south, but did not give further details on the location or the victims' branch of service.
The deaths are the first U.S. fatalities from hostile action in Afghanistan this year. One U.S. service member has died of non-combat causes so far in 2010.
The British soldier died while on foot patrol Sunday in Helmand province, the British Ministry of Defense said.
Afghan insurgents are increasingly turning to improvised explosive devices also called roadside bombs in their fight against Afghan and international forces. Of the 304 U.S. military deaths in Afghanistan last year, 129 were due to IEDs, according to a tally by The Associated Press.
Also Monday, NATO said a joint Afghan-international force discovered a huge cache of marijuana and turned it over to police for destruction. NATO said the cache contained up to 28,000 cubic feet of marijuana; that's the equivalent of about seven standard semi-trailers.
As the U.S. and other Western nations have tried to help Afghanistan stamp out its poppy fields the country is the world's leading opium producer an increasing number of farmers have turned to marijuana, which is receiving less attention from authorities.