Nine people were killed, including five children, in a bomb attack on a polio unit in southwestern Pakistan on Friday, officials said.

The bomb, which was attached to a motorcycle, exploded near a motorized rickshaw carrying schoolchildren in Mastung, a district in Balochistan province, according to local police chief Fateh Mohammad. The rickshaw also carried police officers assigned to protect the polio workers.

Mohammad said five children were killed along with a police officer and two bystanders. Also, 17 people were injured in the attack.

Wasim Baig, a spokesman for the health department, said some of the injured have been shifted to a hospital in Quetta, the capital of Balochistan province. He said seven people died at the scene and two men who were seriously injured died in hospital.

Targeted polio campaign in Pakistan

Mastung Police Chief Rehmat Ullah said a police van was attacked on its way to a health center to escort polio workers for the door-to-door vaccination campaign.

The campaign, which began on Monday, aims to vaccinate 45 million children under the age of five after a wave of new cases threatened the country. 41 cases of polio have been reported in 71 districts of Pakistan this year.

Militants likely to be suspected

No one immediately claimed responsibility for the bombing, but suspicion will likely fall on separatist groups and Pakistanis. Taliban. These militants have recently stepped up attacks on security forces in the country.

Days before the bombing, militants attacked a health center used in the polio vaccination campaign in the northwestern district of Orakzai. The attack sparked a shootout that killed two policemen and three attackers.

Militants often target police and health workers during polio campaigns, claiming vaccination efforts are a Western conspiracy to sterilize children. Pakistan is one of only two countries, along with Afghanistan, where the spread of polio has never been stopped.

Prime Minister Shehbaz Sharif responds

Pakistani Prime Minister Shehbaz Sharif denounced the recent attack, as did the Chief Minister of Balochistan, Sarfraz Bugti. Both have pledged to continue the war against the insurgents until the country is rid of them.

Balochistan has seen a long-running insurgency by separatist groups demanding independence from the central government.

One of the separatist groups, the Baloch Liberation Army, has also attacked foreigners. BLA claimed responsibility for a bombing that targeted Chinese citizens outside an airport in the southern city of Karachi last month. The attack killed two Chinese workers and injured eight people.

This article includes reporting from the Associated Press.