Khalilzad reached the Qatari capital on Friday after the US State Department on Wednesday announced that he would rejoin the talks "to discuss steps that could lead to intra-Afghan negotiations and a peaceful settlement to the ongoing conflict in the country", TOLO News reported.
An initial round of talks was called off three months ago by US President Donald Trump after a Taliban attack in Kabul that killed an American soldier.
The sources said on Friday that after finalizing an agreement with the US, the Taliban will commit to reducing the level of violence.
Before his arrival in Doha, Khalilzad was in Kabul for two days during which he held talks with top Afghan government officials and prominent politic including former President Hamid Karzai.
"Discussions were held on three topics, first the US and the Taliban will resume their direct talks, and they will try to focus on the issue of reduction of violence and the intra-Afghan negotiations," said Shahzada Massoud, former advisor to Karzai.
During the Kabul trip, Khalilzad urged the Afghan government to step up efforts to create an inclusive delegation.
But Gulbuddin Hekmatyar, the leader of Hizb-e-Islami, has said that the Afghan government remains one of the major obstructions in the way of peace.
"The only factor that obstructs the peace, the one who wants the continuation of war and foresees that its survival requires continuation of war is the present government," he said.
But Sediq Sediqqi, the spokesman for President Ashraf Ghani, said: "If someone thinks that the government is a hurdle on the way of peace, this unawareness shows the poor understanding of the individual or groups who say it."
( With inputs from IANS )