The US is engaged in talks with the Taliban, Afghan President Hamid Karzai has said, in the first high-level confirmation of US involvement.
Mr Karzai said that "foreign military and especially the US itself" were involved in peace talks with the group.
Hours later, suicide bombers attacked a Kabul police station, killing nine.
Earlier this month, US Defence Secretary Robert Gates said there could be political talks with the Taliban by the end of this year.
The US is due to start withdrawing its 97,000 troops from Afghanistan in July.
It aims to gradually hand over all security operations to Afghan security forces by 2014.
Summer of fighting
"In the course of this year, there have been peace talks with the Taliban and our own countrymen," Mr Karzai told a Kabul news conference on Saturday.
"Peace talks have started with them already and it is going well. Foreign militaries, especially the United States of America, are going ahead with these negotiations."
He gave no details as to whether the discussions involved Taliban officials with US authorities, or a go-between.
Shortly after the announcement, a number of suicide bombers attacked a police station near the finance ministry in the Afghan capital. The interior ministry said there were three bombers, but other officials said there were four.
The Taliban said they carried out the attack.
The Afghan interior ministry said nine people were killed: five civilians, three police officers and one intelligence official. Twelve people - 10 civilians and two police - were also injured. The attack has now ended.
''A group of suicide attackers got inside police district one," Mohammad Ayub Salangi, Kabul's police chief, told the BBC. "We surrounded the area.''
One of the bombers detonated his suicide vest, while two others were shot dead by police. Some reports said a fourth bomber was killed in an exchange of fire with security forces.