In a 2013 file photo, hundreds of trucks wait to enter Pakistan at the the border crossing at Torkham Gate in Afghanistan.

KABUL, Afghanistan — A senior leader of the Islamic State group in Afghanistan was killed Monday, a day before representatives of Afghanistan and Pakistan pledged to mount a joint effort to defeat the militants.

A government spokesman said Afghan forces had killed Saad Emarati, whom he identified as a key Islamic State commander in the region.

Tuesday’s meeting of the trilateral commission, which includes the two countries and NATO, came three days after an attack claimed by Islamic State on a demonstration of Shiite Hazaras in Kabul killed at least 80 people and injured more than 200.

It was the deadliest attack in the Afghan capital since U.S.-led forces toppled the Taliban in 2001 and the first in the city to be claimed by the Sunni militant group. The Islamic State’s operations have been largely confined to eastern mountainous regions along Afghanistan’s border with Pakistan.

Afghan Defense Ministry spokesman Mohammad Radmanesh said all sides at the meeting of the commission, which normally deals with border issues, emphasized they would work together to defeat the militants.

On Monday, NATO spokesman Brig. Gen. Charles H. Cleveland said international cooperation would be needed to tackle Islamic State in Afghanistan.

“At the end of the day, these issues of terrorism are regional issues and they absolutely require not only Afghan participation, but Pakistani participation and certainly international community participation at all points and at all locations to be able to address these threats,” Cleveland said.

The Associated Press reported Tuesday that Afghan forces had launched a new military offensive against the Islamic State in eastern Afghanistan.

Meetings of the commission are held about four times a year. Radmanesh said border tensions were also discussed, and a statement by the Afghan Defense Ministry said all sides were committed to solving the ongoing border disputes between the two countries.

Last month, several people died in cross-border clashes over Pakistan’s moves to tighten border controls at the well-trafficked Torkham crossing.

Qadir Sediqi contributed to this report.

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