Afghan and Pakistani troops battled along their border, Afghan residents and officials told AFP on Sunday, with the fighting coming alongside multiple strikes including the former US air base at Bagram.
Months of cross-border clashes have flared since Thursday when Afghanistan launched an offensive along the frontier, with Pakistani forces hitting back on the border and from the skies.
Residents in multiple areas bordering Pakistan told AFP of overnight fighting, while two civilians were killed in drone strikes, according to the Nangarhar province information department and police.
North of the capital Kabul, air strikes "hit Bagram air base" according to a resident who AFP is not naming for security reasons.
A second resident said "it was very strong, which shook the area. There was smoke and fire coming out north of the airport", describing the dawn raid as "very terrifying".
The provincial spokesman, Fazl ul Rahim Maskin Yar, said Pakistani jets "attempted to bomb" the base, but there were no casualties or damage.
Pakistan acknowledged bombing key cities Friday including Kabul and Kandahar, which is home to Afghanistan's supreme leader, but has not commented on Sunday's strikes.
In Kabul, AFP journalists heard an explosion followed by successive gunfire.
Taliban government spokesman Zabihullah Mujahid said "anti-aircraft fire is being directed at Pakistani aircraft".
There was an increased presence of security forces in Kabul on Sunday, with more checkpoints in the city centre.
Drones were also heard by an AFP journalist in the border province of Khost, while in Jalalabad city -- between Kabul and the border -- an AFP photographer saw a jet.
The Afghan government's deputy spokesman, Hamdullah Fitrat, said Pakistani fire had killed 36 civilians across multiple provinces since Thursday, which Islamabad has not commented on.
Residents in multiple areas of Afghanistan's Khost province told AFP the two sides were engaged in clashes overnight, while the spokesman for a military unit reported heavy fighting in neighbouring Paktia province.
At Torkham border crossing -- a key gateway for Afghans returning from Pakistan -- fighting was reported by the Nangarhar province information department.
Afghan officials said Thursday's border offensive was a response to earlier air strikes that killed civilians, which Pakistan said targeted militants.
- 'Stop the war' -
On Saturday, AFP spoke to Khost residents who had fled their homes near the frontier.
"We demand from the international community and the whole world to put pressure on Pakistan to stop the war," said 46-year-old displaced resident Javed, who only gave one name.
Diplomatic efforts have failed to secure a truce, with Saudi Arabia and Qatar among those engaged in efforts to halt the fighting.
Islamabad accuses Afghanistan of failing to act against militant groups that carry out attacks in Pakistan, which the Taliban government rejects.
Many attacks have been claimed by the Tehreek-e-Taliban Pakistan (TTP), a militant group that has stepped up assaults in Pakistan since 2021, the year the Taliban authorities returned to power in Kabul.
This week's escalation marked the first time that Pakistan has focused its air strikes on Afghan government facilities, analysts noted, a stark change from previous operations that it said targeted militants.
Pakistan's information minister, Attaullah Tarar, said on Saturday that 41 locations across Afghanistan had been hit by air strikes since its operation began.
More than 350 Afghan soldiers have been killed in the fighting, the minister said.
Islamabad said earlier 12 of its soldiers had been killed.
Fitrat, Afghanistan's deputy spokesman, said more than 80 Pakistani soldiers were killed and 27 military posts captured.
The Afghan government earlier put the death toll among its troops at 13.
Casualty claims from both sides are difficult to verify independently.
The violence of recent days is the worst since October fighting killed more than 70 people on both sides, with land borders between the neighbours largely shut since.
Several rounds of negotiations between Pakistan and Afghanistan last year followed a ceasefire brokered by Qatar and Turkey.