File photo of Islamic State members.
A suicide bombing of a Shiite mosque claimed by the Islamic State group killed at least 28 people in the Yemeni capital Wednesday, ratcheting up tensions ahead of the first White House summit between the US and regional power Saudi Arabia.
The bombing, the latest in a wave of killings claimed by the militant Sunni group, came hours after the Red Cross said a gunman killed two of its Yemeni employees in the war-torn country's rebel-held north in a "deliberate" attack.
IS said a man identified as Qusai al-Sanaani blew himself up after sunset prayers inside the Al-Muayad mosque in the northern Jarraf district, home to many senior figures from the Shiite Huthi rebels that control Sanaa.
The militants said a bomb-laden vehicle parked nearby also exploded as medics arrived on the scene, bringing the death toll to at least 28 people and wounding some 75 more, according to medical officials.
An AFP reporter heard two loud explosions followed by many sirens as ambulances rushed to the scene.
Body parts were blown several metres (yards) away from the scene and nearby buildings were damaged, witnesses said, adding that Huthi gunmen were deployed after the attack to set up new checkpoints across the capital.
The attack was to "avenge Muslims against the Rafidah (Shiites)," IS said in a statement on Twitter.
Its account was confirmed by sabanews.net, the website of the Iran-backed Shiite Huthi rebels that control Sanaa.
Radical Sunni Muslim group IS considers Shiites to be heretics and has claimed similar bombings of other Shiite mosques in Sanaa as well as in Kuwait and Saudi Arabia.
Sunni power Saudi Arabia is leading a coalition that has been bombing the Iran-backed Huthis, which has driven the rebels out of Yemen's second city Aden and four other southern provinces and is now fighting for control of the third city of Taez.
US President Barack Obama is expected to raise the campaign at the first, long-delayed White House summit with Saudi Arabia's King Salman on Friday, particularly concerns over the impact the bombing has had on civilians.
Already 80 per cent of Yemen's population of 26 million are in desperate need of aid, and nearly 1.5 million have been driven from their homes in the five-month war.ICRC staff 'brutally' killed
Earlier on Wednesday, the International Committee of the Red Cross said a gunman killed two of its employees in an "appalling" and "brutal" attack.
The pair had been travelling north of Sanaa with two other colleagues in vehicles "clearly" marked with the Red Cross emblem, said the Geneva-based ICRC.
"Sadly, two of our staff were brutally killed on their way back from Saada to Sanaa," spokeswoman Rima Kamal said.
Saada is the northern stronghold of the Huthis, who are at war with loyalists of exiled President Abedrabbo Mansour Hadi.
Kamal said the unidentified gunman opened fire on the two vehicles after stopping them in Amran province, which has been under Huthi control since last year.
"One of our colleagues passed away on the spot while another sustained critical injuries and was transferred to an MSF (Doctors Without Borders) hospital... where he passed away shortly after," she told AFP. The two others were unharmed.
The head of the ICRC delegation in Yemen, Antoine Grand, identified the dead as a field officer and a driver and condemned "in the strongest possible terms what appears to have been the deliberate targeting of our staff".
Sitara Jabeen, an ICRC spokeswoman in Geneva, said that "after this incident we have stopped all our movements in the country for the time being," although Grand said it would be "premature" to decide the impact this would have on the group's operations.
The ICRC said it was not immediately clear who carried out the attack, noting there had been a number of security incidents involving the organisation in recent months.
On August 25, the ICRC said it had suspended its operations in Yemen's second city Aden after gunmen robbed its main office while holding staff at gunpoint.
The organisation has stepped up its relief activities in Yemen since the rebels entered Aden in March prompting Hadi to flee to neighbouring Saudi Arabia, which has led a military intervention to restore him to power.