Dozens of fighters were killed in overnight border clashes between Pakistan and Afghanistan, both sides said on Sunday, in the most serious fighting between the neighbours since the Taliban came to power in Kabul.

Officials say the closure of border crossings for bilateral trade between Afghanistan and Pakistan has extended into a second day after deadly weekend clashes spiked tensions

According to Pakistani security officials, Pakistan carried out air strikes in Kabul and on a marketplace in eastern Afghanistan on Thursday, which triggered retaliatory attacks by the Taliban. Pakistan has not officially acknowledged the air strikes.

Tensions are high after Islamabad demanded the Taliban take action against militants who have stepped up attacks in Pakistan. The Taliban deny that Pakistani militants are present on its soil.

Key border crossings between Pakistan and Afghanistan were closed on Sunday after fierce clashes erupted overnight following Taliban accusations that Islamabad had carried out air strikes this week, officials said.

As it elevates its relationship with India, Afghanistan’s Taliban government is striking a delicate balance in the region.

China is concerned about recent clashes between Pakistan and Afghanistan and has asked the two countries to protect its nationals and investments in the region, Beijing's foreign ministry said on Monday.

Afghanistan said Sunday it killed 58 Pakistani soldiers in overnight border operations, in response to what it called repeated violations of its territory and airspace. Pakistan's army gave far lower casualty figures,

The Ministry of Foreign Affairs of Qatar released a statement on Sunday, expressing concern over the rising tensions between Pakistan and Afghanistan, and urging both countries to exercise restraint

The Taliban government accuses Pakistan of bombing Kabul and a market in eastern Afghanistan. A blast occurred Thursday night in Kabul near key government buildings.