KABUL, Afghanistan (AP) — A suicide bomber blew himself up in eastern Afghanistan on Saturday, killing 21 people and wounding another 41, most of them believed to be Taliban fighters who had gathered to celebrate a three-day cease fire marking the Islamic holiday of Eid al-Fitr, a police official said.

Nangarhar provincial Police Chief Ghulam Sanayee Stanikzai said the devastating explosion came as previously unthinkable scenes of unarmed Taliban fighters celebrating Eid, often alongside Afghan security forces, played out in cities throughout the war-shattered country on Friday and again on Saturday.

Within hours of the explosion President Ashraf Ghani announced he would extend a nine-day cease-fire that was to expire on Sunday and which he had unilaterally announced last week. The cease-fire was to end at the conclusion of the Eid holiday, which follows the monthlong fasting month of Ramadan.

Ghani offered no details of the extension, including how long it would be in effect. The Taliban's leader, Haibatullah Akhunzada, on Monday separately announced a three-day truce to mark the Eid holiday. The Taliban cease-fire took effect at midnight on Thursday.

Ghani in his statement announcing the extension called on the Taliban to reply in kind. He also said that a cease-fire could be accompanied with visits to their prisoners and treatment for their fighters at hospitals in Afghanistan.

Ghani also repeated his promise that everything could be on the negotiation table, including the presence of foreign forces.

Earlier this week Taliban leader Akhundzada said he wanted direct talks with the United States before engaging in negotiations with the Afghan government. There was no immediate Taliban reply to Ghani's latest offer of an extension.

In a statement Saturday, U.S. Secretary of State Mike Pompeo welcomed Ghani's offer of an extension to the cease-fire, adding that the U.S. "stands ready to work with the Afghan government, the Taliban, and all the people of Afghanistan to reach a peace agreement and political settlement that brings a permanent end to this war."

While no one has yet claimed responsibility for Saturday's explosion in Rodat district of eastern Nangarhar province, the Islamic State affiliate, which did not sign on to the cease-fire, has a strong presence in the area. Previously, IS fighters have clashed with Taliban, who have rejected their demands for a caliphate.

Meanwhile Atta-ul-Rahman Salim, deputy head of Afghanistan's High Peace Council, said Taliban fighters from across the country were entering into government-controlled areas to visit their families "and they were being welcomed by government security forces."

In eastern Logar province, dozens of Taliban on motorcycles roared through the provincial capital of Pul-e-Alam, some of the vehicles festooned with the Afghan flag. Provincial police spokesman Shahpur Ahmadzai told The Associated Press that the Taliban were unarmed and no one was allowed into the city with weapons.

Abdullah Faizani, a Taliban fighter from Logar's Baraki district, said it had been seven years since he has been to the provincial capital.

Although he wanted an extended cease-fire, he said he would not lay down his weapons permanently until "all the foreign troops leave Afghanistan."

In northern Kunduz province, Doctor Abdul Majhid said nearly 2,000 Taliban were seen celebrating in the city, many of them with family and friends but also several were seen celebrating with Afghan Security Forces.

"We are feeling that these days are golden days for us, it is so peaceful," said Majid.

In southern Kandahar, Haji Gulalai said he welcomed the cease-fire.

"I'm so happy for the cease fire in Afghanistan, and I am hoping peace forever."

In Afghanistan's northern Baghlan province, Asadullah Shabaz, head of the provincial council, said unarmed Taliban joined in prayers at a local mosque.

"We are all just so tired of war," he said.