“I demand immediate investigation & action against perpetrators of this heinous act,” Sharif tweeted.

Sources said that the incident took place when Pakistan’s charge d’affaires and his staff were present in the embassy.

Although Pakistan does not officially recognise Afghanistan’s Taliban government, it kept its embassy open even as the hardline Islamists took over in August last year, and maintains a full diplomatic mission.

Pakistan has complicated relations with the Taliban, with Islamabad long accused of supporting the Islamists even while backing the US-led invasion of Afghanistan that toppled them following the 9/11 attacks.

The Foreign Office has summoned the senior Afghan diplomat posted in Islamabad and strongly condemned the attack.

An embassy official told AFP a lone attacker “came behind the cover of houses and started firing”.

“The ambassador and all the other staff are safe, but we are not going outside of the embassy building as a precaution,” he said.

Taliban security officials were not immediately available for comment.

State Minister for Foreign Affairs Hina Rabbani Khar, who recently returend from Afghanistan after meeting with her Afghan counterpart, also condemned the attack targeting Pakistan’s Head of Mission Ubaid Nizamani.

“Prayers & the nation’s thanks to Sepoy Israr Mohammad who is critically wounded,” she tweeted.