SANAA: At least 28 people were killed and 75 others wounded in two bombings near a Shia mosque in a northern district of the Yemeni capital Sanaa on Wednesday, media run by the city's ruling Houthi militia said.

Al-Masirah television cited on its Twitter account the spokesman of the Houthi-controlled health ministry as saying that the casualty toll was a preliminary figure.

The Saba news agency said in a text message that the first explosion was caused by a suicide bomber in the al-Mo'ayyad mosque, followed by a car bomb blast that targeted medics outside the building. It said there were 25 dead and wounded.

The self-styled Islamic State (IS) group in Yemen has claimed responsibility for the twin bomb attacks.

In a statement on Twitter, they said that a man identified as Qusai al-Sanaani blew himself inside the mosque in the northern Jarraf district after sunset prayers.

The radical Sunni Muslim IS added that a bomb-laden vehicle parked nearby exploded as medics arrived on the scene.

The attack was to “avenge Muslims against the Rafidah (Shia),” said the statement.

Witnesses said the car bomb exploded while people were carrying out the wounded from inside the mosque, adding to the casualties.

They reported heavy deployment of Huthi gunmen, who set up new checkpoints across the capital right after the bombings.

One witness, Hamid Ali, said the explosions left body parts and bloodied floors in the mosque frequented by both Sunni and Shia Muslims. Wounded pleaded for help.

Gunmen kill 2 Yemeni Red Cross workers in rebel-held area

Earlier Wednesday, gunmen shot dead two Yemenis working for the International Committee of the Red Cross as they were traveling from the northern Saada province to the capital, Sanaa, the group said.

Rima Kamal, an ICRC spokeswoman in Sanaa, says the two were killed in Amran province.

The UN's humanitarian coordinator for the country, Johannes Van Der Klaauw, and UN humanitarian coordinator Stephen O'Brien both condemned the attack on the Red Cross workers.

Both Amran and Saada are fully controlled by the Houthis.

A civil war in Yemen escalated in March when a coalition of Arab states led by Saudi Arabia intervened to roll back the hold of the Houthi militia over much of the country and to reinstate the government from its exile in Riyadh.

Yemen has been mired in violence since Shia rebels, known as Houthis, swept down from their stronghold in Saada and captured Sanaa last September.

The Houthis are fighting alongside army units loyal to former President Ali Abdullah Saleh against forces loyal to exiled President Abed Rabbo Mansour Hadi as well as southern separatists and local militias. A Saudi-led and US-backed coalition has been launching airstrikes against the rebels since March.

Last month, pro-government forces backed by Saudi-led airstrikes drove the rebels out of Yemen's southern port city of Aden after heavy fighting.

Read more: Saudi-led coalition batters Yemen with intense raids

More than 4,500 people are reported to have been killed in the Arabian Peninsula country's conflict.