In a report released on Sunday, the United Nations mission in Afghanistan said that the first six months of 2018 were the deadliest first half of any year in the war so far, claiming the lives of 1,692 civilians, a 1 percent increase over the first six months of 2017. That increase came despite the cease-fire.

The report said that when the government and Taliban cease-fires overlapped on June 15-17, the only civilian deaths the United Nations recorded were attributed to attacks by the Islamic State. Over all, during that six-month period, ISIS was responsible for 52 percent of the civilian deaths, while the Taliban were responsible for 40 percent, the report said. Only 3 percent of civilian casualties were attributed to the American-led international coalition.

Mr. Mujahid denounced the report, claiming that it had been “manufactured in close coordination with the U.S. Embassy” and that it showed the United Nations “sympathy with American invaders and the cover-up of their daily crimes.”

The Taliban spokesman said that the group had not abandoned the use of suicide attacks, and that it would continue to use them against targets outside the cities.

“Our bosses do not allow us to carry out attacks in the cities quite so often because we want to be careful not to cause civilian casualties,” Mr. Mujahid said. “This does not mean there won’t be any attacks in the cities. Especially in Kabul. It is not that we stopped or gave up.”

Mr. Murtazawi, the president’s spokesman, said the cease-fire demonstrated to the Taliban that many of their fighters were tired of the war, as insurgents mingled congenially with civilians on the government side. Mr. Murtazawi said that recent fatwas by religious leaders in Afghanistan and in Saudi Arabia renouncing the Afghan war had also had an effect. “They don’t have an answer to those fatwas,” he said.

The spokesman for the Afghan High Peace Council, Sayed Ihsan Taheri, said the cease-fire was an important first step toward real peace talks. “Without doubt, after the cease-fire, the level of fighting has decreased and so has the number of attacks,” he said.