At least one police officer and two civilians were killed and dozens injured when a suicide bomber attacked a police vehicle in the southwestern Pakistani city of Quetta, according to the police.
The Tehreek-e-Taliban Pakistan (TTP) armed group, also known as the Pakistani Taliban, claimed responsibility for the attack on Wednesday, two days after announcing the end of a June ceasefire agreement with the government.
Ghulam Azfar Mahesar, the Deputy Inspector General (DIG) of Quetta Police, told reporters that the targeted vehicle was transporting security personnel assigned to protect polio vaccination campaign workers in the provincial capital of Pakistan's Balochistan province.
Mahesar stated that the incident in the Buleli district injured at least twenty police officers. He added that two additional vehicles sustained damage during the attack.
Javed Akhtar, an official at the government hospital in Quetta, told Al Jazeera that among the civilian casualties were a four-year-old girl and a woman.
Prime Minister Shehbaz Sharif condemned the explosion and mourned the loss of civilians and a police officer.
Workers dedicated to eradicating polio are performing their duties without fear for their lives. "The eradication of polio is among the government's highest priorities," he said.
Federal Interior Minister Rana Sanaullah also released a statement condemning the attack and requesting a thorough investigation.
The Chief Minister of Balochistan, Abdul Quddus Bizenjo, vowed to combat the "cowardly act." "All those involved in this incident and those who aided them will be held accountable," he said.
The TTP later claimed responsibility for the attack in a statement.
"This attack was carried out in retaliation for the death of Omar Khalid Khorasani after the end of the ceasefire was announced. Our attacks will continue," the statement read.
Khorasani was a senior TTP leader who was killed in Afghanistan in August by a car bomb.
Earlier this month, the group attacked a second police vehicle in Lakki Marwat, a city in the northwest province of Khyber Pakhtunkhwa, resulting in the deaths of six police officers.
Armed assailants in Pakistan have frequently targeted polio vaccination teams. Nearly 100 people associated with the vaccination campaign have been killed across the nation over the past decade.
At least five attacks on polio teams have occurred this year, with the most recent occurring in October when an unidentified assailant shot and killed a police officer providing security for a polio vaccination health worker in the city of Pishin, Balochistan.
The attacks occurred during an increase in polio cases in Pakistan, the only country other than Afghanistan where the crippling neurodegenerative disease remains endemic.
This year, Pakistan reported 20 new cases of polio, all of which occurred in Khyber Pakhtunkhwa.
The attack in Quetta also occurred as the England cricket team was touring Pakistan for its first test series in 17 years. The first match of the three-test series will begin in Rawalpindi on Thursday.