Article published on the 2009-07-06 Latest update 2009-07-06 14:31 TU
A US marine stands guard next to an Afghan elder in Afghanistan's lower Helmand River Valley.
(Photo: Reuters)
A senior Afghan intelligence official said the four were Americans but the US military and Nato's International Security Assistance Force (ISAF) would not comment on their nationalities.
Thousands of US and British forces are continuing with a major offensive against the Taliban in the south of the country.
An ISAF officer said four ISAF soldiers died "due to an improvised bomb explosion in northern Afghanistan". Provincial intelligence chief General Abdul Majid Azimi said their vehicles were hit by a blast as they crossed over a bridge while travelling by convoy in Kunduz province's Khan Abad district.
The men were US nationals who were training the police, he said, adding that two children were also wounded.
The attack comes after at least two people were killed in a suicide bombing in a separate incident at a checkpoint outside Kandahar airfield in southern Afghanistan on Monday.
On Monday the Taliban in Afghanisan said said they would thwart the operation that had been launched by Nato's Isaf force, saying that in response to the western offensive they had launched "Operation Foladi Jal ('iron net')"
They also said that they had captured a US soldier whom the Isaf force had gone missing last week.