United Nations United States: Yemen's warring parties have agreed on a ceasefire from April 10 followed by peace talks a UN envoy said Wednesday raising hopes of a breakthrough in a conflict that has devastated the country.

On another front a US air strike on an Al-Qaeda training camp killed at least 40 fighters in a major blow to the jihadists who have been expanding their territory in the impoverished Arab state.

Violence has escalated in Yemen since September 2014 when Iran-backed Shiite Huthi rebels stormed the capital Sanaa and forced the internationally recognised government to flee south to the second city of Aden.

"The parties to the conflict have agreed to a nationwide cessation of hostilities beginning April 10 at midnight in advance of the upcoming round of the peace talks which will take place on April 18 in Kuwait" UN special envoy Ismail Ould Cheikh Ahmed told a news conference in New York.

More than 6300 people have been killed in Yemen since a Saudi-led coalition -- which includes Kuwait -- began an air war in March last year to push back the Huthi offensive.

Previous UN-sponsored negotiations between the Huthis and government officials failed to reach a breakthrough while a ceasefire went into force on December 15 but it was repeatedly violated and the Saudi-led coalition announced an end to the truce on January 2.

Only last month the UN envoy warned that the warring parties were unable to agree on terms for a new round of peace talks but those divisions appear to have been overcome.

"The aim is to reach an agreement which will end the conflict and allow the resumption of an inclusive political dialogue" Cheikh Ahmed said Wednesday telling reporters that he had held intense discussions with both the government and the rebels.

United Nations Security Council Resolution 2216 calls for the rebels to withdraw from seized territories and disarm.

The envoy said he hoped the cessation of hostilities would allow safe and unhindered humanitarian access to millions of suffering Yemenis.

The year-long coalition campaign has faced criticism over civilian casualties.

The UN said earlier this month that Saudi-led raids were responsible for the vast majority of the estimated 3200 civilian deaths in the Yemen war.

- Dozens 'removed from battlefield' -

Jihadists have exploited the security vacuum to expand in the south of Yemen seizing parts of Hadramawt including its provincial capital Mukalla in April last year.

The US air strike on Tuesday in Hajr in the vast southeastern province of Hadramawt killed at least 40 militants and wounded 25 more a provincial official told AFP.

A tribal source who confirmed the toll said the casualties were new Al-Qaeda recruits training at the camp.

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

Yemen-based Al-Qaeda in the Arabian Peninsula is regarded by Washington as the network's most dangerous branch and has carried out deadly attacks on the West in the past.

The United States has waged a long-standing drone war against AQAP militants killing several of its leaders.

But Tuesday's raid by American warplanes was unusual because US strikes usually target a small number of suspected Al-Qaeda members while they are travelling in a vehicle.

The raid "deals a blow to AQAP's ability to use Yemen as a base for attacks" that threaten US citizens Pentagon spokesman Peter Cook said.

"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."

In the past few weeks Al-Qaeda and the rival Islamic State group have tightened their grip on parts of the main southern city of Aden where the government has set up its temporary base.

The Arab coalition began targeting jihadists for the first time last week in Aden.

In Abyan another southern province tribesmen captured a suspected local Al-Qaeda chief identified as Hilmi al-Zinji and handed him over to authorities in the government-held region security officials said.

Fearing further strikes Al-Qaeda militants on Wednesday evacuated public buildings they had occupied in Mukalla and deployed five military vehicles around a hospital in the city.

AFP