KABUL - Six people were killed and 13 wounded Tuesday in two separate insurgent bombings in southern Afghanistan, according to the governor's spokesman in restive Helmand province. Four civilians were killed and two wounded when a private car struck a roadside bomb in the Gereshk district of Helmand, a southern province where much of the rural countryside is controlled by the Taliban. Two other civilians were killed and 10 wounded when a suicide bomber on a motorcycle detonated a bomb in a crowded market in Helmand's Marjah district, said Omar Zowak, spokesman for the provincial governor. A police officer also was wounded in the explosion. Zowak told the Los Angeles Times that the Taliban was responsible for both attacks. The Taliban denied responsibility for the market attack, which came at a time when insurgents are increasingly targeting civilians, aid workers and Afghan security force members as U.S. and international combat troops are withdrawing. The Taliban has taken responsibility for previous bombings and roadside attacks that have killed or wounded civilians. There was no statement from the government condemning the Tuesday's attacks. Afghan President Hamid Karzai routinely condemns the U.S. for raids on villages or air strikes on insurgents that accidentally kill civilians; he has demanded an immediate end to such attacks as a condition for signing a proposed 10-year security agreement with the United States. Karzai last month requested and received a letter from President Obama pledging that U.S. forces will enter Afghan homes after 2014 only under "extraordinary circumstances" and only when U.S. lives are directly at risk. Karzai, however, rarely condemns Taliban suicide or roadside bombings that indiscriminately kill civilians - or even those that kill or wound his own security forces. On Monday, the Taliban claimed responsibility for a suicide truck bomber who killed four Afghan police officers and wounded 17 others in an attack on a government district center in Wardak province. There was no statement from Karzai's government Monday condemning the Taliban, which praised the "martyrdom attacker." In a report in July, the United Nations said civilian casualties increased 23% in the first six months of 2013 over the same period in 2012. The world body blamed the Taliban and other insurgents for 74% of the 3,852 civilian casualties during that period. In an interview last week, U.S. Air Force Maj. Gen. Ken Wilsbach, who commands coalition air operations in Afghanistan, said troops take extraordinary measures to avoid civilian casualties and investigate every allegation. He pointed out that the Taliban directly targets civilians and doesn't investigate deaths in such attacks. Years from now, Wilsbach said, "historians will likely take away that the [coalition] force was unbelievably disciplined with respect to this issue" of civilian casualties. Baktash is a special correspondent.