Three NATO-led US soldiers were killed in roadside bomb blasts in southern Afghanistan on Saturday, while a similar attack in the country's north took the lives of three Afghan policemen, officials said, according to dpa. The three soldiers were killed when their convoy was hit by two roadside bombs in southern Afghanistan, the NATO-led International Security Assistance Force (ISAF) said in a statement. The alliance statement did not reveal the nationalities of the soldiers, but a US military spokesman in the region confirmed that the dead soldiers were Americans and that the incidents took place in Kandahar province. Roadside bomb attacks, the use of which has recently become more common among Taliban militants, resulted in the deaths of more than half of the 74 soldiers, including 43 US military members, killed in Afghanistan last month. July marked the deadliest month for international forces since their deployment to the country in late 2001. More than 90,000 international troops - more than half of them from the US - are currently stationed in Afghanistan. Meanwhile, three Afghan policemen, including the head of security for the Dahna Ghori district of northern Baghlan province, were killed when their vehicle was blown up by a roadside bomb on Saturday, Jaweed Basharat, a spokesman for the provincial police chief said. Afghanistan's northern provinces, which had been one of the country's most stable areas, have seen an upsurge in Taliban-led attacks in recent months. Afghan and international troops, mainly US, British and Canadian soldiers, are taking part in several operations in the country to push the militants out of areas they control and provide a safer environment for the country's scheduled August 20 presidential elections. Taliban militants, who were driven from power some eight years ago, have vowed to disrupt the elections, which would be the second direct vote for an Afghan president in the history of the country.