Despite statements of unity, there are vast policy differences between the Arab states, say experts
The agreement at a weekend Arab summit to establish a joint military force has raised serious doubts about prospects of such a force becoming a reality on the ground, experts say.
Egyptian President Abdel Fattah al-Sisi announced the accord on Sunday at the end of the summit he hosted in the Sharm el-Sheikh resort area, setting a four-month timeframe for the 22-member Arab League to decide on the composition and rules of engagement of the joint force.
"The notion of a truly joint Arab military force still remains an aspiration rather than a reality," said Frederic Wehrey, an expert at the Carnegie Endowment for International Peace.
He said it faced "inter-operability problems, political distrust amongst the states and a lack of realistic training".
A host of questions remain unanswered, starting with how many member states would participate and the strength of the force.
Key decisions also have to be made on whether it would be a permanent force, on where it would be based and its command structure.
"I don't think there is a lot of substance to this force," said James Dorsey, a Middle East analyst with the Singapore-based S. Rajaratnam School of International Studies.
"Despite the statements of unity, there are vast differences between the Arab states and that was evident with the situation in Yemen," he said.
The Arab League has for months stressed the "pressing need" for a joint force to combat "terrorist groups" such as Islamic State group.
But the Saudi-led Arab air strikes launched last week against Yemen's Iran-backed Shiite Houthi rebels have highlighted the divergent interests and priorities of the League's members.
For Sunni-majority countries, the Houthis' military advance in Yemen was a step too far, following the spread of Shiite Iran's influence in Iraq, Syria and Lebanon.
'Threat to national security'
"The problem is that this force can be seen as a Sunni Arab force. It must therefore prove that its actions will not be guided by sectarianism," said Mathieu Guidere, professor of Arab geopolitics at France's University of Toulouse.
"Some countries will negatively view any interference in their domestic affairs, and perceive it as a threat to national sovereignty," Guidere said.
Iraq, whose Shiite-led government is allied with Tehran, was the only Arab state to officially express reservations about the joint force at the Sharm el-Sheikh summit.
"We will never allow the intervention of non-Iraqi forces on Iraqi soil," Baghdad's Foreign Minister Ibrahim al-Jaafari told reporters on Saturday.
Aaron Reese of the Washington-based Institute for the Study of War said the Yemen coalition provided "a good idea of what a potential force might look like".
Committed states such as Egypt and Saudi Arabia are "likely to also be highly involved in a possible joint force", he said, but it would need more than four months to bring in other countries.
Egypt's army is the largest in the Arab world and one of its best equipped, while Saudi Arabia uses its oil wealth to acquire highly sophisticated equipment.
However, Wehrey said, the Yemen conflict was likely to highlight challenges faced by the use of traditional military power.
"Arab armies are organised for conventional warfare. Their procurement has been focused on high-end prestige items that are more suited to fighting a conventional adversary than insurgents."
Egypt, at the forefront of calls for a joint force, faces the threat of militants in its western neighbour Libya and in its Sinai Peninsula in the east.
Reese said Libya was "a logical future mission" but - as it does not border Saudi Arabia or involve Iran - may be "a less urgent mission for some of the countries that signed on to a joint force".