Chadian soldiers in Mali have killed Mokhtar Belmokhtar, the al-Qaeda commander behind a bloody mass hostage-taking at an Algerian gas plant earlier this year, Chad's military has said.

The Chadian army, whose troops have been at the forefront of the hunt for al-Qaeda-linked fighters hiding in northern Mali, said Belmokhtar was killed during an operation in the Ifogha mountains on Saturday.

"This would be a hard blow to the collection of jihadists operating across the region that are targeting American diplomats and energy workers" - Ed Royce,

US Republican Representative

The Algerian national, a veteran of the war in Afghanistan whose smuggling activities earned him the nickname of "Mr Marlboro", had broken away from al-Qaeda in the Islamic Maghreb (AQIM) weeks ago to form a group called Signatories in Blood.

His death would be a major blow to Islamist rebels in northern Mali who have been pushed into their mountain

strongholds by French and African forces.

"On Saturday, March 2, at noon, Chadian armed forces operating in northern Mali completely destroyed a terrorist base ... The toll included several dead terrorists, including their leader Mokhtar Belmokhtar," Chad's armed forces said in a statement read on national television.

Belmokhtar claimed responsibility for the seizure of dozens of foreign hostages at the In Amenas gas plant in Algeria in January in which more than 60 people were killed.

The French military, which is leading the offensive in northern Mali, has so far said it cannot confirm the information.

The purported death of Belmoktar comes a day after Chad's president said their troops killed Abou Zeid, the other main al-Qaeda commander in the region, a claim the French also said they could not confirm.

'Marlboro Man'

Algeria's El Khabar newspaper said on Saturday that Algerian security services, who were the first to report Abou Zeid's death, had found his personal weapon and examined a body believed to be his.

"Confirmation of Abou Zeid's death remains linked to the results of DNA tests done on Thursday by Algeria on two members of his family," it said.

Analysts said the death of the two commanders would mark a significant blow to the rebellion in Mali.

"Both men have extensive knowledge of northern Mali and parts of the broader Sahel and deep social and other connections in northern Mali, and the death of both in such a short amount of time will likely have an impact on militant operations," Andrew Lebovich, a Dakar-based analyst who follows al Qaeda in the Islamic Maghreb (AQIM), told Reuters.

US Republican Representative Ed Royce, who chairs the House Foreign Affairs Committee, hailed the reported killing of "one of the most elusive and deadly terrorists in North Africa" without confirming Belmokhtar's death.

"This would be a hard blow to the collection of jihadists operating across the region that are targeting American diplomats and energy workers," Royce said in a statement.

Before In Amenas, some intelligence experts had assumed the Algerian-born Belmokhtar had drifted away from high-profile attacks in favour of kidnapping and smuggling weapons and cigarettes in the Sahara.

He shared command of field operations for AQIM with Abou Zeid, although there was talk the two did not get along and were competing for power.