A suicide attacker blew himself up Thursday at an entrance to a sprawling base for U.S. and NATO operations in southern Afghanistan, killing at least six civilians, police said. The attacks come at a critical moment in peace talks between the U.S. and the Taliban. (Allauddin Khan/AP)

— Two attacks in southern Afghanistan have left at least 19 people dead over the past two days, Afghan officials reported. The attacks come at a critical moment in peace talks between the United States and the Taliban.

Thursday morning, a suicide bomber killed six civilians near the entrance to a NATO airfield in Kandahar, according to Almai Ayoubi, a provincial spokesman. Two of the dead were children. The Taliban promptly asserted responsibility for the attack.

On Wednesday, 13 people were killed and 20 wounded when a suicide bomber attacked a popular bazaar in the Kajaki district of Helmand province, according to Daud Ahmadi, a spokesman for the provincial governor. An official said the attack targeted a joint patrol of Afghan and international troops.

Gen. John R. Allen, commander of the U.S. forces in Afghanistan, condemned the suicide bombings.

“Mullah Omar has lost all control over Taliban insurgents,” he said in a statement, referring to Mohammad Omar, the Taliban leader. “Otherwise he would immediately denounce these attacks and order his ‘forces’ to stop attacking innocent Afghan civilians.”

Marc Grossman, the U.S. special envoy to Afghanistan and Pakistan, is scheduled to visit Kabul in the coming days — a trip that Afghan officials say will dictate the prospects of peace negotiations. The string of recent attacks is expected to add pressure to the tenuous diplomatic process.

Taliban spokesmen have said that their attacks will continue until a formal agreement has been confirmed and that the group is “utilizing its political wing alongside its military presence.”