The Taliban say they engaged Pakistani jets in the skies over Kabul as the fighting between the Pakistani military and the Afghan militants continues to escalate.

Pakistani jets near Kabul were targeted by Afghan Taliban on Sunday, with blasts and gunfire rocking the city, officials said.

The explosions in Afghanistan's capital come as the most recent clashes between the two countries entered a fourth day. The current escalation marks the heaviest cross-border fighting in years, raising fears of a protracted conflict.

On Sunday, explosions were heard across parts of Kabul before sunrise. They were followed by bursts ‌of gunfire, according to the Reuters news agency. It was not clear if the blasts caused any casualties.

Taliban spokesman Zabihullah Mujahid, however, said that "Kabul residents should not be ‌concerned."

"Air ‌defense attacks were carried out in Kabul against Pakistani aircraft," Mujahid said.

Pakistan has acknowledged bombing key Afghan cities on Friday including the capital, Kabul, and the southern city of Kandahar, where Afghan Taliban Supreme Leader Hibatullah Akhundzada is based.

The AFP cited witnesses as saying air strikes had hit the Bagram air base area, previously a US stronghold, in the country's southeast.

Taliban officials boosted security in central Kabul on Sunday evening, with increased checks on cars, AFP reported.

Pakistan PM cancels Moscow trip

The Afghan Taliban launched an offensive over the 2,600-km (1,615-mile) border after accusing Pakistan of targeting civilians inside Afghanistan.

Pakistan rejected the claim, saying its forces had just targeted militants. Islamabad, in turn, insists that that the Taliban-led regime is sheltering extremists that have conducted attacks in Pakistan, which Taliban officials deny.

Diplomatic efforts led by Saudi Arabia and Qatar have failed to secure a ceasefire so far.

Pakistan's Prime Minister Shehbaz Sharif canceled a scheduled visit to ‌Russia amid the fighting. Moscow has called on both Afghanistan and Pakistan ‌to cease cross-border attacks and ⁠seek diplomacy to resolve their differences.

Attaullah Tarar, Pakistan's information minister, said Pakistani forces have killed some 415 Taliban Afghan soldiersand that only 12 Pakistani soldiers had been killed.

Taliban government's deputy spokesman, Hamdullah Fitrat, said that by their calculations, over 80 Pakistani soldiers were killed and 27 military posts captured.