Pakistan's Defense Minister Khawaja Asif declared "open war" on the Afghan Taliban government in a post on X on Friday morning. 

Khawaja wrote: "Pakistan made every effort to keep the situation normal through direct means and through friendly countries. It engaged in full-fledged diplomacy. Our cup of patience has overflowed. Now it is open war between us and you."

Khawaja's declaration followed a series of Pakistani airstrikes on major Afghan cities, which reportedly came in response to attacks on Pakistani troops.

Earlier Friday, Afghan government spokesperson Zabihullah Mujahid said in a post on his X account that the Pakistani military had conducted airstrikes in parts of Kabul, southern Kandahar and eastern Paktia Province. He said no civilian casualties were reported.

Following the airstrikes, extensive retaliatory operations were reportedly carried out against Pakistani military positions in Kandahar and Helmand, according to the spokesperson.

In a separate statement released early Friday, the Afghan Ministry of Defense said its forces had killed 55 Pakistani soldiers and seized dozens of pieces of Pakistani military equipment during the operations. The ministry said the military actions along the border have now concluded.

The statement also reported Afghan losses, saying eight Afghan security personnel were killed and 11 others were wounded during the clashes.

Meanwhile, a security source from Pakistan told Xinhua the airstrikes came after Afghan Taliban began attacking Pakistani border posts on Thursday evening. 

According to the source, Pakistan targeted key Taliban defense assets in Kabul, Kandahar and Paktia in Afghanistan early Friday as part of Operation Ghazab Lil Haq (Wrath of Justice).

Pakistani Prime Minister's spokesperson Mosharraf Zaidi said in a statement that 72 Afghan militants were killed, more than 120 were injured, 16 posts were destroyed, and seven posts were captured in retaliatory attacks by the country's forces.

The strikes mark the most serious escalation between the neighbors in months, threatening a fragile ceasefire along the 2,600-kilometer (1,615-mile) frontier and deepening a long-running dispute over Islamabad's ⁠accusation that Kabul ‌harbors militants who has stepped up attacks in Pakistan, a charge the Taliban deny.

The cross-border clashes between Afghanistan and Pakistan have drawn concern from the UN Secretary-General Antonio Guterres.

Stephane Dujarric, spokesperson for Guterres, said that the UN chief is following with concern the clashes and urges relevant parties to comply with their obligations under international law and to ensure the protection of civilians.

"Commending mediation efforts by several Member States in recent months, the Secretary-General urges the parties to continue to seek to resolve any differences through diplomacy," Dujarric said.

(With input from agencies)