Taliban militants killed one U.S.-led coalition soldier and wounded 11 others in heavy fighting in southern Afghanistan on Monday (July 17) while the aid workers expressed concerns over the displacement of many civilians in the fighting area in the Afghan south. "In the Trin Kowt district of Uruzgan province yesterday, coalition forces attacked and destroyed a truck that extremists were loading with mortar rounds. A heavy engagement followed with the extremists, and unfortunately one coalition soldier was killed and 11 coalition soldiers were wounded in that battle," said Colonel Thomas Collins, a coalition spokesman in Kabul. Coalition forces also confirmed that the Taliban had taken control of two districts in the southern province of Helmand where heavy fighting is going on. "The Taliban have recently taken control of the towns of Gamser and Nawayi Barekazayi, however the coalition does have observation on those areas and a decisive operation will begin soon. I cannot tell you for security reasons when we will begin the decisive operation, but I can assure you that we will reestablish government authority in those locations soon," said Collins at the press conference in Kabul NATO peacekeeping force will take over from the U.S.-led coalition at the end of the month. Bulgaria said it was sending on Monday its first group of a 70-member contingent to Afghanistan to look after security at Kabul airport for five months starting in August. "The whole contingent will be in place in Kabul by the end of the month," a Defence Ministry spokeswoman said. Aid agencies expressed their concerned over the current situation in the south part of Afghanistan "Many schools that IOM has build in Helmand province have been taken over by Taliban, according to some report there is only two district in Helmand that are under the afghan government control, the rest have reportedly been taken over by insurgent and the situation for the people in southern Afghanistan is very critical because over 90 percent of the Afghan people make their living in agriculture and because of the drought in the south people have been displaced, and now with the growing violence the situation is just getting worst," said Rahilla Zafar, International Organization for Migration in Afghanistan (IOM) press officer. She also added that about 4, 000 civilian were displaced from their homes during fighting. "IOM is trying to locate, so far there have been 4,000 people estimated to be displaced and IOM is working with local villager to locate these people and to provide them with tents and food I teams," said Zafar After days of some of the heaviest fighting since the fall of the Taliban in 2001, coalition forces said they had destroyed a "safe house" of a Taliban commander in Sangin district in Helmand province. The U.S. military said the raid was conducted on Sunday night, but they did not name the commander who was targeted. Foreign forces also said they had a captured a militant leader in the largely peaceful north of the country, along with a large cache of weapons. Amir Gul Hassanyar was captured south of Kunduz on Sunday and is believed to be responsible for numerous attacks using improvised explosive devices, as well as trafficking in illegal weapons and drugs, a coalition statement said. Three Afghan soldiers were killed on Monday when a roadside bomb hit their convoy in Girishk district of Helmand. A member of parliament said Taliban fighters had taken control in a thinly populated southern district of Helmand. The Taliban had occupied Garmser district overnight without any resistance, Sher Mohammad Akhundzada said.