Fighters in Afghanistan fired heavy weapons across the border into a Pakistani military outpost and killed three troops, according to the army.
A firefight ensued with the attackers in Pakistan’s rugged North Waziristan region and several were killed, a military statement said on Saturday.
It was unclear which of the many armed groups in Afghanistan was responsible for the assault.
The incident comes as Afghanistan is reeling from a series of explosions in recent days, including the bombing of a mosque in northern Kunduz province on Friday that killed 33 people, including several students of an adjacent religious school.
Another attack on Thursday on the Abdul Rahim Shaheed school in Kabul killed seven children. It reopened on Saturday with students remembering their fallen classmates with roses.
The striking increase in attacks in Afghanistan – as well as in neighbouring Pakistan – highlights the growing security challenge facing Afghanistan’s Taliban rulers, who swept to power last August in the closing days of the chaotic withdrawal of American and NATO troops ending their 20-year war.
An ISIL (ISIS) affiliate known as the Islamic State in Khorasn Province, which claimed the recent spate of attacks in Afghanistan as well as in neighbouring Pakistan, is proving an intractable challenge.
Islamic State in Khorasan Province is not the only armed group in Afghanistan contributing to the security dilemma facing the Taliban government.
The Pakistani Taliban, known as the Tehreek-e-Taliban Pakistan (TTP) – which the United Nations says numbers about 10,000 in Afghanistan – has stepped up its assault on Pakistan’s military outposts from its Afghan bases.
The Taliban has promised no armed groups would use its soil as a base to attack another country, but Kabul has yet to arrest or hand over any TTP leaders in Afghanistan to Pakistan. Other groups also operating in Afghanistan include China’s Uighurs of East Turkistan Movement, which seeks independence for northwest China, and the Islamic Movement of Uzbekistan (IMU).
After seven of its troops were killed in an ambush earlier this month, Pakistan retaliated with bombing raids inside Afghanistan that locals in eastern Khost province said killed dozens of refugees.
The United Nations confirmed 20 children were killed in the air strikes in Afghanistan’s border provinces of Khost and Kunar.