Egyptian officials said the Yemen airstrikes are to be followed by a ground intervention to further weaken the rebels, known as Houthis, and their allies and force them into negotiations. They have also moved ahead with action in Libya after its collapse into chaos since 2011 and the rise of militants there — including now an affiliate of the Islamic State group that has overrun much of Iraq and Syria. Egypt and the United Arab Emirates have both carried out airstrikes against Libyan militants in the past year.

In their agreement Thursday, the foreign ministers called on the chiefs of staff of the Arab League’s 22-member nations to meet within a month to iron out details of the force, like its budget and mechanism, and report back to the organization.

The Egyptian military and security officials said the proposed force would be made of up to 40,000 elite troops and will be headquartered in either Cairo or Riyadh, the Saudi capital. The force would be backed by jet-fighters, warships and light armor. They spoke on condition of anonymity because they were not authorized to speak to the media.

Arab league officials said some Arab nations had reservations about the creation of a joint force, including Iraq, whose foreign minister, Ibrahim a-Jaafari, has counselled fellow ministers that more time was needed for planning.