Arab leaders ­announced Sunday that they would form a joint military force to intervene in neighboring states grappling with armed insurgencies. It is a dramatic step to quell the unrest that has broken out in the wake of the region’s uprisings, but some analysts warned it could exacerbate the conflicts that have polarized countries and left hundreds of thousands dead.

The announcement at a summit of Arab leaders in Egypt came as warplanes from a Saudi-led coalition carried out scores of airstrikes across Yemen overnight Saturday and again Sunday, the fourth day of a campaign against Shiite rebels known as Houthis. That coordinated operation, involving mostly Arab countries, could represent a prototype for future joint Arab military interventions in the region.

Arab officials said they still need to hammer out the details of the proposed joint force, but broader questions remain over the ability of Arab countries — many of which have killed scores of their own citizens — to stem the region’s wars through military action. Arab armies, while well-equipped, are largely untested and lack the training to fight guerrilla-style conflicts with rebel forces such as the Houthis. From Yemen to Libya to the battlefields of Syria, armed groups have exploited fresh violence to seize power or rout rivals. The result has been deepening polarization and rising death tolls across the region.

“Without a component for political dialogue, this force will be ineffective and even detrimental” to the region, said Abdel Salam Nasia, an independent member of Libya’s parliament who attended the summit in Egypt.

Last month, Egyptian fighter jets carried out airstrikes against militant targets in eastern Libya after jihadists beheaded 20 Egyptian Christians there. Egypt then called for a broader intervention to battle Libya’s militant Islamist groups but was rebuffed by U.S. and U.N. officials seeking a negotiated end to Libya’s violence.

Speaking at the summit Sunday, in the Red Sea resort of Sharm el-Sheikh, Yemeni Foreign Minister Riyadh Yaseen scoffed at the idea of government talks with the Houthis and said that the Saudi-led offensive has been “extremely successful.”

“The operation will end when Yemen is safe and secure. But we will only negotiate with those who are willing to disarm,” he said. “We won’t negotiate with [the Houthis] because they carried out a coup. They used the state’s weakness to take over.”

Saudi Arabia intervened in Yemen after the Houthis toppled the government and captured vast tracts of territory in recent weeks.

The Arab League chief, Nabil al-Araby, said Sunday that the joint force would be deployed at the request of any Arab nation facing a security threat, including from terrorist groups. A panel of regional security officials will meet in the coming months to draw up the size, structure and budget of the effort, he said. Member states have proposed a 40,000-strong force backed by fighter jets, warships and light armor, the Associated Press reported, citing Egyptian security officials.

Arab officials said the region’s unprecedented threats have made a joint security force necessary. Indeed, a wave of uprisings beginning in 2010 deposed at least four Arab leaders after decades of authoritarian rule. But the pro-democracy revolts were soon overtaken by political chaos and the proliferation of armed factions seeking to capitalize on the instability.

“The challenges facing Arab national security are immense,” Egyptian President Abdel Fatah al-Sissi said at the closing session of the Arab League summit. Sissi said the decision to establish a combined military force “defends our [Arab] nation­ . . . and gives it an active role in the future of human civilization.”

In Yemen, the streets of the Houthi-controlled capital, Sanaa, were empty Sunday because of fears of renewed airstrikes, residents said. In the northern Houthi stronghold of Saada, there were unconfirmed reports that airstrikes had destroyed power plants, depriving the province of electricity. Warplanes also struck Sanaa’s airport and the port at Hodeida, crippling Yemen’s already weak infrastructure.

Yet even as Saudi officials said they had not ruled out invading Yemen with ground troops, analysts warned of the perils of sending inexperienced armed forces into a country with rugged mountain peaks and severe water shortages. Such a ground force would also struggle against battle-hardened Houthis who are now the most competent fighters in Yemen. The country’s military has fallen apart because of splits over loyalties and the Saudi ­attacks.

Yezid Sayigh, senior associate at the Carnegie Middle East Center in Beirut, said Saudi forces lack experience in mounting large ground offensives.

“There are all sorts of potential pitfalls” that would accompany a ground incursion in Yemen, he said. “The whole point is that the Houthis have demonstrated that other fighting forces are disorganized, leaderless, and thus these forces collapsed in the face of Houthi assaults.”

Egypt, too, commands a sizable army, but it has struggled to battle a years-long insurgency in the Sinai Peninsula. Its forces have also been attacked on the border with Libya, causing some of the highest casualties among Egyptian troops since the war with Israel in 1973.

“We are wary of military intervention, and we hope the Arab League can provide checks” on the forces leading the push for joint Arab assaults, said Dhia al-Dabbass, Iraq’s permanent delegate to the Arab League.

“The politics of the region are too complex,” he said. “There is no reason why negotiation should not take precedent.”

Habib reported from Sharm el-Sheikh. Mujahed reported from Sanaa. Hugh Naylor contributed from Beirut.

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