US military planes killed dozens of fighters at an Al-Qaeda affiliate’s training camp in a mountainous region of Yemen.

US military planes killed dozens of fighters at an Al-Qaeda affiliate's training camp in a mountainous region of Yemen, the Pentagon said Tuesday.

The raids came almost one year since the Saudi-US aggression started its bombing campaign against Yemen.

Yemeni government and tribal officials had earlier said Saudi-led air strikes killed or wounded dozens at a training camp in Hajr, west of Hadramawt's provincial capital Mukalla.

The early morning raid at a camp used by "more than 70" Al-Qaeda in the Arabian Peninsula fighters "deals a blow to AQAP's ability to use Yemen as a base for attacks that threaten US persons," Pentagon spokesman Peter Cook said in a statement.

"We continue to assess the results of the operation, but our initial assessment is that dozens of AQAP fighters have been removed from the battlefield," Cook said.

"It demonstrates our commitment to defeating Al-Qaeda and denying it safe haven."

It was not immediately clear whether there were any civilians among the casualties.

Tribal sources said wounded militants were taken to a hospital in Mukalla, while witnesses spoke of around nine vehicles rushing casualties out of the area.

Dozens of Al-Qaeda militants were meanwhile seen rushing to the hospital to donate blood, according to residents.

The World Health Organization says fighting in Yemen since March 2015 has claimed the lives of almost 6,300 people, while the UN human rights chief last week said the vast majority of those deaths caused by coalition strikes.