Tehran summoned the Pakistani ambassador to demand that Islamabad stop "terrorists and rebels" from crossing into Iran's border province of Sistan-Baluchistan.
An Iranian military official says Tehran has proof that militants are entering Iran from Pakistan to carry out attacks.
Two Iranian border guards and a Pakistani paramilitary officer have been reported killed in a shooting incident.
A group of leading clerics in Pakistan has condemned the Islamic State (IS) group amid concern that it could find recruits among Islamist militants in the country.
A court in eastern Pakistan has upheld the death sentence of a Christian women convicted of blasphemy four years ago.
Pakistan's army says it has killed at least 21 militants in air strikes targeting suspected hideouts of Islamist insurgents in the country's northwest.
Afghan security officials said they have arrested two senior leaders of the Haqqani network, a hard-line group behind some of the deadliest attacks and kidnappings in the country.
Local officials said at least five people were killed and seven wounded in a suicide attack that targeted a peace committee meeting in a restive Pakistani tribal area.
Senior Pakistani and Indian military officials have spoken to each other in the first high-level contact between the two neighbors since recent border clashes erupted in the disputed Kashmir region.
A Pakistani Taliban spokesman has reaffirmed his allegiance to Islamic State militants and said five other Tahreek-e-Taliban Pakistan (TTP) commanders also have declared loyalty to IS.
Malala Yousafzai and Afghan National Cycling Team member Salma Kakar have made "Time" magazine's annual list of the world's most influential teenagers.
An aide to Pakistan’s Prime Minister Nawaz Sharif says Sharif is unlikely to attend the award ceremony for the Nobel Peace Prize shared by Pakistani activist Malala Yousafzai and Indian activist Kailash Satyarthi.