Three US soldiers were killed in separate bomb blasts in southern Afghanistan on Sunday, as the government in Kabul banned a fertilizer chemical used by Taliban militants to make bombs, dpa reported.
The two US soldiers serving under the NATO-led International Security Assistance Force (ISAF) were killed in a roadside bomb blast, the alliance said in a statement.
The third US soldier was killed in a similar attack in a southern province, NATO said, without providing further details about the incidents or the area where the bombings took place.
The attacks came a day after a similar bombing killed two US soldiers in the same region. The latest deaths bring to 26 the number of US troops killed in Afghanistan so far this month.
More than 110,000 international forces, including nearly 70,000 US troops are currently stationed in Afghanistan. Up to 37,000 additional US and NATO troops are expected to arrive in the country in summer, as part of a military escalation to turn the tide of the nearly nine-year-war.
Meanwhile, Deputy Interior Minister Munir Mangal, deputy interior told a press conference on Sunday that based on recommendations of Afghan security entities, President Hamid Karzai has banned the use, production, storage, purchase or sale of ammonium nitrate in Afghanistan.
He said the Taliban militants, who have waged a bloody insurgency against the Afghan government and its military allies, have increasingly been using the chemical to make bombs.
"The ammonium nitrate is cheaper and easier to carry than other explosives," he said.
Nahim Balouch, deputy chief for National Directorate of Security, Afghanistan's intelligence service told the same press conference that ammonium nitrate had been used in more than 80 per cent of the bombings carried out by the militants.
He said most of the material used in a suicide car bombing in front of a shopping mall last week in Kabul was ammonium nitrate.
At least seven suicide bombers launched a massive attack in Kabul on Monday, killing five people and wounding 71. One of the bombers detonated an explosives-laden ambulance near a shopping mall in the heart of the city, while the rest were killed either by their own explosives or encounters with security forces.
The militants rely heavily on use of roadside and suicide bombings as part of their campaign against the allied forces in the country.