Five NATO soldiers were killed in three separate attacks in Afghanistan at the weekend, the International Security Assistance Force said Sunday.

Four died in two roadside bomb explosions Sunday, in the east and in the south, while another was killed in an insurgent attack in the east on Saturday, ISAF said.

In line with policy, the International Security Assistance Force statement did not name the nationalities of the dead or give any further details.

The latest deaths take the total toll among the US-led coalition so far this year to more than 250, according to the website icasualties.org.

Also at the weekend, Taliban insurgents executed five civilians near Kabul for working with NATO troops, Afghan authorities said Sunday.

The militants captured six Afghans returning home from work at a NATO base in Wardak province south of Kabul, bound their hands, shot them and left their booby-trapped bodies on the road, the provincial governor's office said

But it is roadside bombs, a favourite weapon of Taliban insurgents, that have taken a particularly heavy toll in Afghanistan this month.

Six American soldiers died in a huge blast on July 8 in the east, which is the focus of a NATO push against insurgents along the border with Pakistan.

On the same day, 18 civilians travelling in three vehicles were killed in southern Kandahar province.

Among other notable recent attacks, eight civilians, five Afghan police and two NATO soldiers were killed in three separate explosions last Thursday.

The attacks were blamed on Taliban insurgents -- hardline Islamists who have waged a decade-long campaign to topple the government of President Hamid Karzai, which is backed by 130,000 NATO troops.

For the past five years the number of civilians killed in the war has risen steadily, reaching a record 3,021 in 2011 -- the vast majority caused by insurgents, according to UN figures.