bombings Yemen part of broader sectarian struggle

 The horrific attacks on Shiite mosques in Yemen on Friday highlight a growing and more lethal sectarian struggle in the Middle East that is pitting Iran and its Shiite allies against rival Sunni regimes and militant organizations.

A group claiming to be a Yemeni branch of the Islamic State, composed of Sunni extremists, claimed responsibility for Friday's bombings. They were carried out by as many as four suicide bombers at two mosques controlled by Shiite rebels in Sana'a, Yemen's capital. The claim could not be verified.

Al-Masirah TV, a network owned by the rebels, said 137 worshipers were killed and 345 wounded in the multiple attacks.

The conflict in Yemen, as in Syria and Iraq, is rooted in the centuries-long animosity between the two branches of Islam. The Houthi rebels are Shiites from northern Yemen. They now control the capital and large swaths of the country, which has a Sunni majority.

Sunni extremists, such as al-Qaeda and the Islamic State, are increasingly emerging as champions of beleaguered Sunnis in the Shiite-dominated countries, analysts say.

"Regardless of who attacked the mosques, al-Qaeda's influence and support is expanding dramatically in Yemen" as sectarian tensions grow, said Abdulkader Sinno, an Indiana University professor who has written about insurgent organizations.

Friday's attacks were the deadliest in Yemen in decades and appeared to have targeted Shiite worshipers to fan sectarian flames.

Similar violence

The suicide bombings reportedly happened during noon prayers in the the capital city of Sanaa. The mosques were crowded with worshippers at the time. Video provided by Newsy Newsy

Matthew Levitt, an analyst at the Washington Institute for Near East Policy, said the sectarian conflicts in the Middle East are more intractable and complex than conventional wars between nations because of the religious passions and ancient hatreds.

"The sectarianism were seeing today is much more dangerous," Levitt said.

When Islamic State militants poured into Iraq from Syria last year, many Sunnis residents refused to resist and some cooperated as they routed Iraq's troops. That's because the Sunnis, a ruling minority under dictator Saddam Hussein, felt threatened by the Shiite government in Baghdad and viewed the militants as protectors, even though the residents didn't share the militants' extreme view of Islam.

The sectarian conflicts in Iraq, Yemen, Syria and other parts of the Middle East are part of a broader struggle between powerful Sunni regimes, such as Saudi Arabia, and Iran, the region's Shiite powerhouse.

"It makes things more complicated and nastier," Levitt said. "These are no longer self-contained conflicts."