|CNN Senior International Correspondent Nic Robertson discusses new photographs showing the purported bombers who attacked two Yemen mosques on March 20.|
Multiple suicide bombings on two mosques in Yemen's capital today have left hundreds killed or injured.
Four bombers wearing explosive belts targeted the Badr and al-Hashoosh mosques in Sanaa during midday prayers in what was one of the country's deadliest ever jihadist attacks.
At least 137 are dead and a further 351 people are thought to have been wounded in the devastating blasts, described by eyewitnesses as being like earthquakes.
A group claiming to be the Yemeni branch of Islamic State immediately said they were responsible for the bombings.
Charred bodies and pools of blood were seen at the scene of the explosions while footage from the al-Hashoosh mosque, showed screaming volunteers using bloodied blankets to carry away victims.
At the Badr mosque at least 25 bloody bodies were seen lying in the street and inside the building.
The mosques are mainly used by supporters of the Shi'ite Muslim Houthi group as well as Sunni worshippers.
The group posted an online statement saying that five suicide bombers carried out what it described as a 'blessed operation' against the 'dens of the Shiites'. It also warned of an 'upcoming flood' of attacks against the rebels
The claim offered no proof of their role - but it was posted on the same website that the Islamic State affiliate in Libya claimed responsibility for Wednesday's attack on a museum in Tunisia.
The first bomber was caught by militia guards searching worshippers at the entrance of the Badr mosque.
He detonated his device at the outside gates while a second bomber entered the mosque and blew himself up amid the crowds, according to the official news agency SABA.
One witness from the attack at al-Hashoosh said he was thrown two metres by one of the blasts.
'Blood was running like a river.'
Another witness added: 'I was going to pray at the mosque then I heard the first explosion, and a second later I heard another one.'
Hospitals were urging citizens to donate blood, the Yemeni rebel-owned Al-Masirah TV channel said.
It also reported that a fifth suicide bomb attack on another mosque was foiled in the northern city of Saada, a Houthi stronghold.
A prominent Shiite cleric, al-Murtada al-Mansouri, and two senior Houthi leaders were among the dead, the TV channel reported.
Survivors compared the explosions to an earthquake and said some people were injured by shattered glass falling from the mosque's large hanging chandeliers.
The television channel aired footage from inside the al-Hashoosh mosque, where screaming volunteers were using blankets to carry away victims.
Corpses were lined up on the mosque floor and carried away in pick-up trucks.
The attacks come just two days after 23 people were killed when gunmen opened fire on tourists at a museum in Tunisia.
In Washington, White House spokesman Josh Earnest said the U.S. had seen no indications of an operational link between the Islamic State group and Friday's attacks.
He said the U.S. was investigating to see whether the IS branch in Yemen has the command-and-control structure in place to substantiate its claim of responsibility.
Earnest said it was plausible that IS was falsely claiming responsibility for the incident.
'It does appear that these kinds of claims are often made for a perception that it benefits their propaganda efforts,' Earnest said.