This is the first time security sources loyal to Yemen's internationally recognised government have announced raids against IS footholds

Unmanned aircraft struck two Islamic State group training camps in central Yemen for the first time in the country's conflict, leaving an unknown number of dead, security sources told AFP Monday.

Witnesses said villagers were prevented by tribal leaders from approaching the area and retrieving the dead and wounded for fear of additional strikes.

Locals said the camps, both in Bayda province, were named after prominent IS figures: Yemen chief Abu Bilal al-Harbi and former global spokesman Abu Mohamed al-Adnani, killed last summer in a US air strike.

This is the first time security sources loyal to Yemen's internationally recognised government have announced raids against IS footholds.

IS and its jihadist rival Al-Qaeda have taken advantage of a conflict between the government and Shiite Huthi rebels, who control the capital Sanaa, to bolster their presence across much of the south.

The US is the only force known to operate armed drones over Yemen, but previous known strikes have exclusively targeted Al-Qaeda.

IS, however, has risen to prominence in the country's civil war targeting both army recruits of the government and Shiites, which it considers heretics.

It entered the war in March 2015 with a series of attacks on Shiite mosques in the capital, leaving more than 140 people dead.

The group's last major attack was a suicide bombing in the government stronghold of Aden last December, which killed 48 soldiers.

Al-Qaeda has distanced itself from IS attacks, claiming that it seeks to avoid "the shedding of any Muslim blood" while focusing on fighting the "Americans and their allies."

The Saudi-led coalition, which intervened in Yemen in March 2015 to roll back Huthi rebel gains, has also turned its firepower on Sunni jihadists and backed forces loyal to President Abedrabbo Mansour Hadi.

The Yemen war has killed 8,673 people and wounded 58,636 -- among them many civilians, according to the UN.