Afghanistan and Pakistan have resumed peace talks in Istanbul, four sources familiar with the matter said on Thursday, a day after Islamabad said the discussions had ended in failure.

Three of the sources said the nations had recommenced talks at the request of mediators Turkey and Qatar, to ensure they do not resume border clashes that have killed dozens this month.

One of the sources, a Pakistani security official, said Islamabad would press its central demand at the talks that Afghanistan take action against Islamist militants using its territory as a safe haven and to plan attacks on Pakistani soil.

“Most of the issues between Pakistan and Afghanistan have been resolved successfully and peacefully. A few demands from Pakistan need some extra time as they are difficult to be agreed upon,” said a source close to the Afghan Taliban delegation.

Islamabad accuses the Taliban of harbouring the Pakistani Taliban, a separate militant group hostile to Pakistan, and allowing them to attack Pakistani troops from Afghan territory.

Kabul denies this, saying it has no control over the group.

The sources declined to be named as they are not authorized to comment publicly on the issue.

The Afghan Taliban and Pakistan’s military and foreign office did not immediately respond to requests for comment.