Gulf Arab monarchies have sent thousands of heavily armed troops to reinforce loyalists in Yemen in the battle against Iran-backed rebels, media reported on Monday.

The reinforcements come after a missile attack by the Shia Houthi insurgents on Friday killed 60 Gulf soldiers -- 45 Emiratis, 10 Saudis and five Bahrainis.

The Sunni-ruled Gulf states have remained tight-lipped about the new troops sent mainly by Qatar and Saudi Arabia to Marib province east of Yemen's rebel-held capital Sanaa.

But Qatar's Al-Jazeera news channel reported late on Sunday that 1,000 Qatari soldiers with 200 armoured vehicles have arrived in Marib after crossing the border from Saudi Arabia.

It is the first time Qatari troops are reported to be taking part in operations on the ground in Yemen by the Saudi-led coalition, which in March began an air campaign in support of exiled President Abedrabbo Mansour Hadi.

Saudi Arabia also sent elite units to Marib on Sunday, according to the Saudi daily Asharq al-Awsat and Emirati state news agency WAM.

Yemeni military sources in Marib have spoken of the arrival of some 1,000 Saudi soldiers armed with tanks and other armoured vehicles, as well the Qatari reinforcements.

Military sources have also mentioned preparations in Marib for an offensive against the rebels and their allies, renegade troops loyal to ousted president Ali Abdullah Saleh.

The Houthis swept down from their northern mountain stronghold last year and seized Sanaa unopposed before advancing on second city Aden in March.

After loyalists recaptured the southern port in July, the coalition began a ground operation that has seen the rebels pushed back from five southern provinces.