Iran and Hizbullah, its Lebanese terror proxy, are building a network of militias inside Syria to preserve and protect their interests in the event that President Bashar al-Assad’s government falls or is forced to retreat from Damascus, U.S. and Middle Eastern officials told The Washington Post on Sunday.

According to the sources, the militias are fighting alongside Syrian government forces to keep Assad in power. Officials believe, however, that Iran’s long-term goal is to have reliable operatives in place in the event that Syria fractures into separate ethnic and sectarian enclaves.

A senior Obama administration official cited Iranian claims that Tehran was backing as many as 50,000 militiamen in Syria.

“It’s a big operation,” the official told The Washington Post. “The immediate intention seems to be to support the Syrian regime. But it’s important for Iran to have a force in Syria that is reliable and can be counted on.”

Iran’s strategy, a senior Arab official agreed, has two tracks. “One is to support Assad to the hilt, the other is to set the stage for major mischief if he collapses,” he told The Washington Post.

The officials spoke on condition of anonymity.

Syrian fragmentation along religious and tribal lines is a growing concern for neighboring governments and the administration, as the civil war approaches its third year with little sign of a political solution or military victory for either Assad’s forces or the rebels.

Rebel forces, drawn largely from Syria’s Sunni majority, are far from united, with schisms along religious, geographic, political and economic lines. Militant Islamists, including many from other countries and with ties to al-Qaeda, are growing in power.

One of these terror groups is Al-Nusra Front, a rebel group which has a strong presence on the ground in northwestern Syria and has been blacklisted by the United States as a “terrorist” organization.

Al-Nusra is an affiliate of Al Qaeda, believing in the hope of reviving the Islamic Caliphate that will build a Muslim Empire to eventually rule the world. The group is one of 13 factions in the radical Islamist rebel council that recently announced its secession from the main opposition force.

Despite U.S. efforts to convince members of Assad’s Alawite sect, itself a minority within Islam’s Shiite branch, that their interests lay in abandoning him, Alawite support remains fairly solid, noted The Washington Post.

“Syria is basically disintegrating as a nation, similar to how Lebanon disintegrated in the 70s to ethnic components, and as Iraq did,” Paul Salem, director of the Beirut-based Mideast Center of the Carnegie Endowment for International Peace, told the newspaper. “It’s going to be very hard to put Syria the nation back together.”

“We’re looking at a place which is sort of a zone, an area called Syria, with different powers,” Salem said.

The Iranian government has in the past confirmed sending troops to support President Bashar Al-Assad in his battle against rebels.

Iranian President Mahmoud Ahmadinejad personally sanctioned the dispatch of the experienced officers to ensure that the Assad regime survives the threat to its survival.