KABUL, Afghanistan — After six days of intensive negotiations, Taliban insurgents and U.S. officials meeting in Qatar appeared closer Saturday to an agreement that could result in the withdrawal of American troops after 17 years of war.

Initial reports from Doha, the Qatari capital, said the outlines of an agreement have been reached and a joint statement was imminent, but by Saturday night there were indications of a stumbling block over U.S. demands for a lengthy cease-fire and the inclusion of Afghan officials in talks. The insurgents have demanded that the Trump administration lay out a timetable for a U.S. troop pullback, and they have said they will not stop attacking Afghan and foreign targets until all U.S. troops have been ordered to leave.

The Trump administration has been eager to end the U.S. role in a war that has cost 2,400 American lives and billions of dollars, and President Trump has said he wants to send home half of the 14,000 troops now in the country. U.S. officials have asked the Taliban to guarantee that other militias, such as the Islamic State, won’t be allowed to use Afghanistan as a base for attacking Western interests.

Zalmay Khalilzad, the Trump administration’s special envoy for Afghan peace, left Doha Saturday night and was en route to Kabul for consultations. In a series of tweets, he said the meetings were “more productive than they have been in the past. We made significant progress on vital issues.”