At least 10 civilians were killed and 12 wounded in two separate blasts targeting passenger buses in the city late on Tuesday, police said.

In a separate incident, an explosion caused a power outage leaving several parts of Kabul in darkness. The blasts took place hours after a US official said the American military will hand over its main Bagram Air Base to Afghan forces in about 20 days.

Washington carries out its final withdrawal after nearly two decades of war. The vast base, built by the Soviets in the 1980s, is the biggest military facility used by US and NATO forces in Afghanistan, with tens of thousands of troops stationed there during the peak of America's military involvement in the violence-wracked country.

Handing over bases

Bagram base was the centre for nationwide command and air operations for the past two decades. It also houses a prison that held thousands of Taliban and jihadist inmates over the years.

Washington had already handed over six military bases to Afghan forces before May 1, when it began accelerating the final withdrawal of troops. Last month it completed the withdrawal from Kandahar Airfield in southern Afghanistan, once the second-largest foreign military base in the country. The US withdrawal comes despite bloody clashes across the country between the Taliban and Afghan forces.

Peace talks

Peace talks were launched in September in Qatar between the Taliban and the Afghan government, but so far have failed to strike any deal to end a war that has killed tens of thousands of people over nearly two decades.

On Tuesday, a group of Afghan government negotiators reached Doha in the hope of resuming stalled talks.

"Our team is ready for serious negotiations. There is no military solution to this conflict," Najia Anwari, spokeswoman for the Ministry of Peace, told AFP, adding that no date had been fixed for resuming the talks.

Fawzia Koofi, one of four women negotiators from the government team, said on Twitter before leaving for Doha that she hoped for a "meaningful and result-based negotiation this time to end the bloodshed and suffering of my people".

"We need to see more willingness and sincerity in the talks as the few months ahead of us are crucial for Afghanistan and the region."