The latest round of diplomacy has cleared a path for the Afghan peace process but final hurdles remain before genuine talks to end the war can formally begin, officials and analysts say.
A suicide car bomber attacked a NATO armoured vehicle in the southern Afghan city of Lashkar Gah on Thursday, killing at least three civilians and wounding 31 others, an official said.
The Taliban earlier this month for the first time announced they had reached a preliminary understanding with the government of Qatar to open a liaison office there to facilitate peace talks.

An Afghan soldier who shot dead four French troops has said he did it because of a recent video showing US Marines urinating on the dead bodies of Taliban insurgents, security sources said.

Taliban militants have released a video showing the execution of 15 Pakistani soldiers, whose bodies were found earlier this month, after they were kidnapped in northwestern Pakistan.
A NATO soldier was killed on Saturday in an insurgent attack in Afghanistan, the NATO-led International Security Assistance Force (ISAF) said.
"Six civilians were killed in a suicide attack close to the gates of Kanadahar airport today," said Kandahar police chief General Abdul Razeq.
A suicide bomber on a motorcycle killed seven policemen and two civilians in an attack in Afghanistan's southern Helmand province today, an official said.
The Afghan military says a man in an Afghan uniform opened fire on a group of Americans at a base in the south of the country, killing one US soldier and wounding another.
Afghan police say a group of insurgents has tried to storm a government building in eastern Afghanistan, setting off a firefight that has killed at least four people.
A video showing US forces urinating on dead Taliban fighters prompted anger in Afghanistan on Thursday, but the insurgent group said it would not harm nascent efforts to broker peace talks.
A suicide bomber in a car killed the governor of Panjwai district in southern Kandahar province on Thursday, Afghan officials said.
The Taliban's political wing is ready to enter peace talks to end the war in Afghanistan, but the insurgents will in the meantime continue their armed struggle, the group said on Thursday.
A 39-second video purporting to show Marines urinating on dead bodies in Afghanistan is straining US-Afghan relations but is not expected to undo months of work aimed at brokering peace with the Taliban.
The US has agreed in principle to release high-ranking Taliban officials from Guantánamo Bay in return for the Afghan insurgents’ agreement to open a political office for peace negotiations in Qatar, the Guardian has learned.