SANAA, Yemen — The Sunni terror group ISIS purportedly claimed it committed Friday’s bombings that killed scores of people at two mosques frequented by Shiite rebels in Yemen’s capital — an attack that would mark ISIS’s first large-scale attack in the Arabian Peninsula country.
At least 135 people were killed and 345 were injured when suicide bombers attacked the mosques in Sanaa, according to TV station Al Masirah, an outlet run by the Shiite Houthi rebels who’ve held the capital for months.
Video distributed by Reuters showed people removing bodies from one of the mosques, where a carpeted floor was littered with debris.
If ISIS committed the attack, it would not only be a new challenge to the minority Houthis who swept into Sanaa months ago, but also a challenge to ISIS’s rival, al Qaeda in the Arabian Peninsula, the Sunni extremists more associated with Yemen.
And it also would illustrate a seemingly expanding focus for ISIS, which controls parts of Syria and Iraq and earlier this week claimed Wednesday’s killings of tourists at a museum in Tunisia.
Regardless, Friday’s attacks marked one of the worst recent days of violence during a complicated struggle for control of Yemen, where Houthi rebels — Shiites in a predominantly Sunni country — already faced resistance from AQAP and from supporters of ousted President Abdu Rabu Mansour Hadi.
A written statement, purportedly from ISIS, claimed that ISIS executed Friday’s attacks, calling them “a tip of an iceberg.”
The statement, posted on a site that previously carried ISIS proclamations, said five suicide bombers targeted Houthis in Sanaa.
A separate audio message, also posted on ISIS-affiliated websites, claimed five ISIS suicide bombers killed dozens of “Houthi infidels.” The voice is similar to one featured in Thursday’s audio message in which ISIS claimed responsibility for Wednesday’s attack at the Bardo Museum in Tunisia.
CNN cannot independently verify the legitimacy of Friday’s statements.
Among those killed in Sanaa was prominent Houthi religious leader Murtatha Al Mahathwari, the state-run Saba news agency said.
A separate explosion rocked a government compound in the Houthi stronghold city of Saada — 180 kilometers (112 miles) northeast of Sanaa — killing two people and seriously injuring a third, according to Abu Khalil Al Ameri, a local Houthi security official.
If ISIS executed Friday’s bombings, it would be a “big deal indeed,” in part because ISIS was thought only to have a fledgling presence in Yemen, CNN terrorism analyst Paul Cruickshank said.
“The dominant group there is al Qaeda in Yemen. ISIS and al Qaeda in Yemen can’t stand each other,” Cruickshank said. “But … whoever is responsible, I think, (is) trying plunge the country into civil war.”
That’s a complication for a number of parties, including the United States, which until the Houthis took Sanaa had counted on the Yemeni government for support in its long-running battle against AQAP.
In Friday’s assaults at Al Badr mosque and Al Hashoosh mosque in Sanaa, suicide bombings started inside the buildings, followed two minutes later by explosions outside, perhaps to target those fleeing the preliminary blasts, two senior Houthi leaders in Sanaa said.
At Al Badr mosque, the outdoor explosion was another suicide bombing; at Al Hashoosh mosque, the exterior blast was a car bomb, the two leaders said.
“We check people and watch at times, but it’s a mosque, and we can’t check everyone who enters,” said Ali Al Emad, a Houthi security worker at Al Hashoosh mosque.
The mosques serve members of the Zaidi sect of Shiite Islam — the sect to which the rebel Houthi militants belong.
The mosque attacks came six months after the Houthis — who have long felt marginalized by the majority Sunnis in Yemen and have battled the central government for more than a decade — entered Sanaa. That sparked battles that left than 300 people dead before a ceasefire was agreed to that month.
The Houthis gradually took control, seizing the presidential palace in January and forcing President Hadi to resign.
Hadi initially was put under house arrest, but he escaped last month, fleeing to the southern port city of Aden and declaring himself to still be President.
The Houthis took control of military forces stationed near Sanaa, including the air force, as they overtook the central government there in January.
Though the Houthis hold sway in Yemen’s north, they have less influence in the south. Clashes between Houthi-controlled forces and military units still loyal to Hadi stepped up this week in Aden, about 300 kilometers (186 miles) southeast of Sanaa.
On Thursday, a Yemeni jet commanded by the Houthis fired missiles at a palace where Hadi was taking refuge in Aden, injuring no one but marking an escalation in the fighting.
The jet flew from Sanaa to the palace in Aden, where the jet conducted the strikes, a senior air force official said on condition of anonymity.
Hadi was at the Aden palace compound when the first missile struck the grounds, but he fled safely, a Hadi aide said, also on condition of anonymity.
A second missile struck near the compound but, like the first, injured no one, two officials in Aden said.
The airstrikes came on the same day that opposing Yemeni military forces — those commanded by Houthis, and those led by officers loyal to Hadi — battled in Aden, leaving at least 13 people dead and 21 others injured, Aden Gov. AbdulAziz Hobtour said.
The Houthi takeover of Sanaa stunned governments of Western nations, including the United States, which had a long relationship with Yemen’s leader, working with the regime to target AQAP militants.
U.S. officials frequently say AQAP is one of the most dangerous terror groups in the world, based on their attempts to attack U.S. interests, including an attempt to blow up an American jetliner over Detroit in December 2009.
The United States, along with most European and Persian Gulf countries, suspended operations in their embassies this year after the Houthis took Sanaa.
But the United States’ anti-AQAP drone program in Yemen continued, with a U.S. drone strike killing senior AQAP cleric Harith bin Ghazi al-Nadhari and three other people in Shabwa province on January 31.