DUBAI (AFP) - The Islamic State militant group claimed responsibility for suicide bombings Friday in the Yemeni capital that killed 142 people at mosques attended by Shi'ite militiamen.

In an online statement, the previously unknown Sanaa branch of IS warned that the bombings were "just the tip of the iceberg".

"Infidel Huthis should know that the soldiers of the Islamic State will not rest until they eradicate them... and cut off the arm of the Safavid (Iranian) plan in Yemen," the statement from the Sunni Muslim extremist group said.

Shi'ite Huthis, who overran Sanaa in September, are accused of receiving support from Iran.

The statement claimed responsibility for bombings that targeted two mosques in Sanaa and another in the Huthis' Saada stronghold, where an assailant detonated his explosives belt outside a mosque after failing to get in.

It is the first time that IS has claimed any attacks in Yemen where Al-Qaeda remains the most prominent militant group.

Al-Qaeda in the Arabian Peninsula, considered by Washington to be the deadliest affiliate of the global extremist network, remains strongly active in Yemen.