US-Taliban talks are "on the right path", special envoy Zalmay Khalilzad said Thursday, but warned there was more work to be done, adding: "you can't eat an elephant in one bite".
It comes after Khalilzad confirmed to media this week that Washington and the Taliban had a "draft framework" in place for a deal which could pave the way for the insurgents to hold peace talks with Kabul.
The development was described by experts as a "milestone" in the grinding 17-year Afghan conflict, but prompted concerns from Afghans and observers who feared it could see US troops withdraw from the country before a lasting peace deal is reached with the government in Kabul.
"The path to peace doesn't often run in a straight line," Khalilzad tweeted, adding that the situation was "complex".
"We made significant progress on two vital issues: counter terrorism and troop withdrawal.
"That doesn't mean we're done. We're not even finished with these issues yet, and there is still work to be done on other vital issues like intra-Afghan dialogue and a complete ceasefire."
Sceptics have "rushed to judgement", he said, but added that "you can't eat an elephant in one bite!" "And a forty year old war won't be resolved in one meeting, even if that meeting runs for close to a week."