The blast followed a series of attacks in the capital Kabul which have heightened concern that Afghanistan could tip into a spiral of violence.

The NATO force in Afghanistan will change on December 31 from a combat mission to a support role, with troop numbers cut to about 12,500 -- down from a peak of 130,000 in 2010.

"A suicide bomber on foot detonated his explosives among people who were attending a funeral ceremony in Burka district this morning," Aminullah Amarkhil, police chief of Baghlan province, told AFP.

"Initial reports show nine people, including two police, were killed and around 18 wounded."

Amarkhil said the funeral was for a tribal elder in Baghlan, a province on the main road from Kabul to Mazar-e-Sharif that has suffered worsening security in recent years.

Taj Mohammad Taqwa, the district chief of Burka, confirmed the death toll.

"The target was probably a number of high-ranking police officials and provincial council members who were attending the ceremony," he said. "They are unharmed."

There was no immediate claim of responsibility.

President Ashraf Ghani, who came to power in September, has vowed to bring peace to Afghanistan after decades of conflict, saying he is open to talks with any insurgent group.

A Taliban attack on Saturday in Kabul killed a South African father running an education charity and his two teenage children.

Insurgents have targeted foreign guest houses, embassy vehicles, US troops, Afghan army buses and a female member of parliament in recent weeks.

They also launched a four-day attack on a major military base in the southern province of Helmand that was only handed over by NATO a month ago, and killed 12 soldiers at a separate outpost in the same province on Saturday.

Afghan soldiers and police have suffered soaring casualties on the battlefield, with more than 4,600 killed this year as they take on the Taliban with less assistance from the US military.

Afghanistan faces a fragile economy and declining aid funds as well as worsening violence.

Ghani and chief executive officer Abdullah Abdullah will visit NATO headquarters in Brussels Monday before attending a conference in London in a public show of unity after they signed a power-sharing deal in September.

Hamid Karzai, president from 2001-2014, opened preliminary contacts with the Taliban but they collapsed acrimoniously last year.