PESHAWAR, Pakistan — A roadside bomb exploded near a vehicle carrying security forces in Pakistan’s restive northwest, killing four officers and wounding five others, officials said Thursday, and on the same day two schoolboys were killed when a mortar shell exploded near them elsewhere in the northwest.

The roadside attack took place on Wednesday in South Waziristan district, a former stronghold of the Pakistani Taliban, local policeman Dilawar Khan said.

No one immediately claimed responsibility for the attack, but Pakistani Taliban, known as Tehrik-e-Taliban Pakistanhas stepped up its attacks in the region since its ally Afghan Taliban seized power in neighboring Afghanistan in 2021.

Later in the day, a mortar fired by insurgents landed near a road in the Tirah valley of Khyber Pakhtunkhwa province on Wednesday, killing two schoolchildren who were walking to school, police said.

The Pakistani military has launched dozens of operations against the Pakistani Taliban and other insurgents in South Waziristan and other nearby former tribal regions, but the militants continue to carry out frequent attacks.

Pakistan’s Interior Minister Mohsin Naqvi met Chinese Ambassador Jiang Zaidong in Islamabad on Thursday to brief him on the investigation into an attack on Tuesday in which a security guard was shot and wounded. two Chinese citizens at a textile factory in the port city of Karachi about a private dispute.

China has often called for better security for its citizens who are in Pakistan to work for Beijing’s multibillion-dollar business. Belt and Road Initiative. An unknown number of Chinese also work in the country’s factories.