Islamabad, Pakistan (CNN) -- At least 40 people were killed and scores were wounded in overnight airstrikes by the Pakistani military on areas in the country's northwest where militants are based, a senior military official said Tuesday.
Later Tuesday, in southwestern Pakistan, an explosion on a bus carrying pilgrims killed at least 22 people.
The airstrikes in the northwest came after recent militant bombings that struck military targets.
The strikes by fighter jets and helicopter gunships targeted areas in North Waziristan, a Taliban stronghold bordering Afghanistan and Khyber Pakhtunkhwa province.
It was unclear whether there were any civilian casualties in the attacks. The military official said the dead and wounded were militants.
The strikes follow two recent deadly attacks claimed by the Pakistani Taliban that targeted military areas.
On Sunday, a blast at an army checkpoint in the northwestern city of Bannu killed more than 20 people and wounded dozens more.
And on Monday, a suicide bombing at a market near the Pakistani army's headquarters in Rawalpindi left 13 people dead -- some of them military personnel -- and more than two dozen wounded.
After the Bannu attack, Pakistani Prime Minister Nawaz Sharif said he was canceling a planned trip to Davos, Switzerland, where the World Economic Forum takes place this week.
Also in Pakistan on Tuesday, at least 22 Shia Muslim pilgrims from neighboring Iran were killed in an explosion on the bus that was carrying them in the southwestern province of Balochistan, a local official said.
More than two dozen others were injured in Tuesday evening's blast in the province's Mastung district, said Shafqat Anwar, an assistant commissioner for Mastung.
Women and children were among those killed and hurt, he said.
Details about what caused the blast weren't immediately available.
Saima Mohsin reported from Islamabad, and Zahir Shah reported from Peshawar, Pakistan.