KABUL (Reuters) – At least 18 people, including Afghan security forces personnel, were killed in a suspected car-bombing in eastern Afghanistan on Thursday, hours before a three-day ceasefire was to begin in the country for the Muslim festival of Eid al-Adha, officials said.

The ceasefire, announced by the Taliban, comes at a time violence has risen across the war-torn country as U.S.-brokered peace talks between the militant group and an Afghan government-mandated committee await the completion of a prisoner exchange between the two sides.

The Taliban denied responsibility for the bombing in a statement from spokesman Zabihullah Mujahid.

The explosion targeted Afghan security forces in Pul-e-Alan, the capital of the eastern province of Logar and civilian casualties are also feared, according to Shahpoor Ahmadzai, the spokesman for the provincial police.

He added it was unclear whether it was a car or suicide bombing, but that security forces had gathered for duty in the city to prepare for security measures for Eid al-Fitr, which will be celebrated in Afghanistan on Friday.

The head of the province’s council, Hasib Stanekkzai, told Reuters it was a car-bombing and put the toll at 18 dead and 22 injured.

Since the U.S.-Taliban agreement in February, 3,560 Afghan security forces personnel have been killed in attacks by militants, according to Afghan President Ashraf Ghani.

The U.N. Assistance Mission in Afghanistan said in a report this week that more than 1,280 Afghan civilians had been killed in the first six months of the year, mainly as a result of fighting between Afghan government forces and the Taliban.

U.S. Special Representative for Afghanistan Zalmay Khalilzad was in Kabul on Wednesday to discuss the need to keep violence down by all sides after the ceasefire and the completion of the prisoner exchange, according to a statement by the U.S. Embassy in Kabul.

(Reporting by Abdul Qadir Sediqi in Kabul and Ahmad Sultan in Nangarhar; Writing by Gibran Peshimam; Editing by Mark Potter)