Roadside bombs killed five foreign troops in Afghanistan on Saturday, extending a series of daily attacks that have lifted the death toll for foreign forces this year to over 100.

Officials also reported that two Afghan soldiers died in a bombing and several militants were killed in each of three separate clashes with U.S.-led coalition forces, including one close to the capital.

Violence continues unabated in Afghanistan, despite the presence of thousands of extra U.S. and NATO troops and fresh pledges of financial aid to the struggling government under President Hamid Karzai.

In Saturday's deadliest incident, a bomb killed four coalition troops and seriously wounded two others in the southern province of Kandahar, a coalition statement said. It provided no details.

To the east, a Polish soldier from the separate NATO-led force died when a bomb hit his patrol shortly after midnight in the Dila district of Paktika province. Jacek Poplawski, a Polish military spokesman in Warsaw, said four other soldiers were wounded, but their lives were not in danger.

The bombings cap a particularly bloody week.

NATO and Afghan troops backed by warplanes on Wednesday attacked up to 400 Taliban militants who had seized Arghandab, a strategic valley dotted with orchards within striking distance of the main southern city of Kandahar.

According to the Defense Ministry, 56 fighters and two Afghan soldiers died during the overnight operation, though the provincial governor put the militants' toll at over 100.

The swift military success was tempered by concern at how easily militants had infiltrated a region dominated by one of the region's strongest tribes, and forced NATO to mount a massive counter-operation.

It was also offset by a series of deadly attacks in the south and east which have taken this year's death toll for foreign troops to 106, according to an Associated Press tally.

Bomb, rocket and gun attacks had already killed four British soldiers, two American sailors, two U.S. Marines and one other member of the U.S.-led coalition this week.

Also Saturday, a roadside bomb hit a vehicle carrying Afghan army troops in the Sori district of Zabul province, killing two and wounding three others, provincial police official Faridullah Khan said.