Quadruple suicide bombers on Friday hit a pair of mosques controlled by Shiite rebels in the Yemeni capital, Sanaa, unleashing blasts through crowds of worshippers that killed at least 137 people and wounded around 350 others in the deadliest violence to hit the fragile war-torn nation in decades.
A group claiming to be a Yemeni branch of the Islamic State group said it carried out the attack and warned of an "upcoming flood" of attacks against the rebels, known as Houthis, who have taken over the capital and much of Yemen. The claim, posted online, could now immediately be independently confirmed and offered no proof of an Islamic State role.
If true, Friday's bombing would be the first major attack by IS supporters in Yemen and an ominous sign that the influence of the group that holds much of Iraq and Syria has spread to this chaotic nation, where a powerful wing of the rival militant group Al Qaeda already operates. The claim was posted on the same website in which the Islamic State affiliate in Libya claimed responsibility for Wednesday's deadly attack on a museum in Tunisia.
The rebels, known as Houthis, have controlled the capital since September and have been locked in battle with Sunni Al Qaeda fighters in various parts of the country. An official with Al Qaeda in Yemen said his group was not behind Friday's attack.
The four bombers attacked the Badr and al-Hashoosh mosques, located across town from each other, during midday Friday prayers, traditionally the most crowded time of the week, according to the state news agency. Both mosques are controlled by the Shiite Houthis, but they also are frequented by Sunni worshippers.
The rebel-owned Al-Masirah TV channel said the casualty figures had reached 137 dead and 345 injured and reported that hospitals were urging citizens to donate blood. It also reported that a fifth suicide bomb attack on another mosque was foiled in the northern city of Saada — a Houthi stronghold.
Scenes from the two mosque showed devastation, with a number of children among the dead. Footage from the al-Hashoosh mosque showed screaming volunteers using blankets to carry away victims. A prominent Shiite cleric, al-Murtada al-Mansouri, and two senior Houthi leaders were among the dead, the TV channel reported.
Two suicide bombers attacked the Badr mosque. The first bomber was caught by militia guards searching worshippers at the mosque entrance and detonated his device at the outside gates. Amid the ensuing panic, a second bomber was able to enter the mosque and blow himself up amid the crowds, according to the official news agency SABA.
Another pair of suicide bombers attacked the al-Hashoosh mosque. One witness said he was thrown two meters away by one of the blasts.
A survivor from the Badr mosque attack, Sadek al-Harithi, described the scene as, "an earthquake where I felt the ground split and swallow everyone."
In an online statement signed by the so-called "Sanaa Province Media office," a group claiming to be the Islamic State branch in Yemen claimed responsibility for the attack, saying that the four Sanaa suicide bombers blew themselves up among crowds of Houthis.
"This operation is just a glimpse of an upcoming flood, God willing," the group said in the statement. "We swear to avenge the bloodshed of Muslims and the toppling of houses of God."
It directly addressed the Houthis by saying, "The soldiers of the Islamic State ... will not rest until we have uprooted them, repelled their aggression, and cut off the arm of the Iranian project in Yemen," a reference to claims that Shiite powerhouse Iran is backing the rebels.
An Al Qaeda official told The Associated Press that Al Qaeda in the Arabian Peninsula, the Yemeni branch of the terror network, did not carry out the attack. He pointed to earlier statements by the group that prohibited striking mosques. He spoke on condition of anonymity because he is not authorized to talk to the press.
The Shiite rebels' power grab has fanned fears of a full-blown civil war in Yemen with sectarian overtones. Shiites, mainly from the Zaidi branch, make up about a third of Yemen's population. Allied with ousted former Yemeni president Ali Abdullah Saleh, the Houthis now control at least nine of Yemen's 21 provinces, and the government of President Abed Rabbo Mansour Hadi has been driven to the southern city of Aden.
Friday's attacks come a day after violent clashes in Aden between rival troops loyal to Saleh and Hadi that left 13 dead and forced closure of the city's international airport.