A gunman killed a top member of the Afghan peace council in Kabul, authorities have said.
The assassination is another blow to efforts to negotiate a political resolution to the decade-long war.
Mohammad Zahir, head of the Kabul police department's criminal investigation division, said former Taliban official-turned Afghan peace negotiator Arsala Rahmani was killed in the west part of the capital.
Mr Zahir saids an unknown attacker in a vehicle shot Mr Rahmani who was travelling in another car on his way to work.
Former head of the council Burhanuddin Rabbani, a former president of Afghanistan, was assassinated on September 20, killed by a suicide bomber posing as a peace emissary from the Taliban.
On Twitter, the US Embassy in Kabul called the assassination of another peace council member "a tragedy".
Mr Rahmani, a former member of parliament, was one of about 70 influential Afghans and former Taliban appointed by President Hamid Karzai to try to reconcile with the insurgents.
He served as minister of higher education during the Taliban regime, which ruled Afghanistan for five years and sheltered al-Qaida before being driven out of power in the US-led invasion in late 2001.
Mr Rahmani was one of several former members of the Taliban who were removed from a UN blacklist in July 2011. The decision by a UN committee eliminated a travel ban and an assets freeze against him and the others - a move seen as key to promoting the peace effort.