US Secretary of State John Kerry will arrive in Egypt on Saturday amid US attempts to form a broad coalition to tackle Islamic State (IS) militants.

Kerry will meet Arab League chief Nabil al-Arabi in Cairo on the latest leg of his Middle East tour.

He has enlisted the support of 10 Arab states so far, including Saudi Arabia and Qatar, but on Friday he ruled out Iran joining the US-led coalition.

On Friday, the CIA said IS has as many as 30,000 fighters in Syria and Iraq.

IS controls large parts of both countries and its fighters have become notorious for their brutality, but in recent weeks they have been targeted by US air strikes.

On Wednesday, President Barack Obama unveiled plans for an expansion of the US campaign against IS.

He vowed to “hunt down terrorists who threaten our country, wherever they are.”

The 10 Arab countries to have signed up to the coalition are: Egypt, Iraq, Jordan, Lebanon, Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, and the United Arab Emirates.

Later on Saturday, Kerry will meet with Arabi, the Secretary General of the Arab League, to discuss how the coalition will act against IS.

Kerry says military and intelligence experts will spend the coming days working out how each state will contribute.

But speaking in Turkey on Friday, he said it would be “inappropriate” for Iran to join the group because of its “engagement in Syria and elsewhere”.

Iran has backed the government of President Bashar al-Assad in Syria, while the US and several European and Gulf countries have supported the rebel factions fighting to overthrow him, reports the BBC.