The offensive at multiple points along the frontier follows a series of border clashes and Pakistani strikes on Afghanistan in recent months.

"In response to repeated violations by the Pakistani military, large-scale offensive operations were launched against Pakistani military bases and military installations," Taliban government spokesman Zabihullah Mujahid said.

The governor's office and residents in the province of Kunar told AFP that military action was under way, while Afghan officials said armed forces were operating in multiple other provinces.

Pakistan said the attack was "being met with immediate, and effective response".

Afghanistan "opened unprovoked fire on multiple locations" across the border in Pakistan's Khyber Pakhtunkhwa province, Islamabad's information ministry said.

The Taliban government spokesman told AFP that Afghan forces had captured more than 15 Pakistani outposts in two hours.

"Dozens of (Pakistani) soldiers have been killed and we have transferred 10 dead bodies to Kunar and other areas. There are also several wounded and caught alive," Mujahid said.

There were no immediate reports of Afghan casualties.

- Months of border violence -

The military operation follows Pakistani strikes on Nangarhar and Paktika provinces overnight into Sunday, which the UN mission in Afghanistan said killed at least 13 civilians.

The Taliban government said at least 18 people were killed and denied Pakistan's announcement that the military operation left more than 80 militants dead.

Both sides also reported cross-border fire on Tuesday, but without casualties.

Relations between the neighbours have plunged in recent months, with land border crossings largely shut since deadly fighting in October that killed more than 70 people on both sides.

Several rounds of negotiations followed an initial ceasefire brokered by Qatar and Turkey, but the efforts have failed to produce a lasting agreement.

Saudi Arabia intervened this month, mediating the release of three Pakistani soldiers captured by Afghanistan in October.

Islamabad accuses Afghanistan of failing to act against militant groups that carry out attacks in Pakistan, which the Taliban government denies.

Pakistan's military launched its air strikes on Afghanistan days ago following a series of deadly suicide blasts.

They included an attack on a Shiite mosque in Islamabad that killed at least 40 people and was claimed by the Islamic State group.

The militant group's regional chapter, Islamic State-Khorasan, also claimed a deadly suicide bombing at a restaurant in Kabul last month.

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