Five American service members have been killed in a helicopter crash in southern Afghanistan, officials said.
The deaths took the total number of US troops killed on Monday to seven, making it the deadliest day for US forces so far this year. Two US special operations forces were gunned down hours earlier in an insider attack by an Afghan policeman in eastern Afghanistan.
The Nato military coalition said in a statement that "initial reports" showed no enemy activity in the area at the time of the crash and that the cause is under investigation.
A US official said all five of the dead were American.
The helicopter went down outside Kandahar city, the capital of Kandahar province. The five dead included everyone on board the UH-60 Black Hawk, said Major Adam Wojack, a spokesman for the international military coalition in Afghanistan.
Their deaths make 12 US troops killed so far this year in Afghanistan. There were 297 US service members killed in Afghanistan in 2012, according to an Associated Press tally.
It was the deadliest crash since last August, when a US military helicopter crashed during a firefight with insurgents in a remote area of Kandahar. Seven Americans and four Afghans died in that crash.
In March 2012, a helicopter crashed near the Afghan capital, Kabul, killing 12 Turkish soldiers on board and four Afghan civilians on the ground, officials said. And in August 2011, insurgents shot down a Chinook helicopter, killing 30 American troops, mostly elite Navy Seals, in Wardak province in central Afghanistan.
Also on Tuesday, a statement from the Interior Ministry said insurgent attacks killed six Afghan civilians.
Four died when the tractor they were on struck a roadside bomb in the southern province of Helmand on Monday. Then on Tuesday, two women were killed when a mortar fired by insurgents hit their house in the same province.