A US air strike in Yemen last month killed the senior Al-Qaeda official who appeared in a video claiming the deadly January attack on French magazine Charlie Hebdo, a monitor said Thursday.

Nasser bin Ali al-Ansi, who was killed in the April strike along with his eldest son and other fighters in the port city of Mukalla, also appeared in Al-Qaeda videos claiming the holding and death of US hostage Luke Somers, SITE Intelligence Group said.

The announcement of his death came in a video posted Thursday on Twitter by Al-Qaeda in the Arabian Peninsula -- which Washington considers the international terror network's deadliest branch.

The air raid appears to have been carried out overnight on April 21-22, when witnesses in Mukalla said an apparent US drone strike on a vehicle parked near the presidential palace in the city killed six suspected Al-Qaeda militants.

SITE described Ansi as "a senior AQAP official and military strategist".

Ansi appeared in the video released on January 14 in which AQAP claimed it had carried out the attack on Charlie Hebdo magazine in Paris to avenge its publication of cartoons of the Prophet Mohammed.

Citing an AQAP video issued in November, SITE said the Taez-born Ansi had pursued jihad in Bosnia in 1995 before travelling to Afghanistan via Yemen and Kashmir to train in Al-Qaeda camps.

It was in Afghanistan that the terror network's now slain leader Osama bin Laden "tasked him with administrative affairs, before he entered the military field," according to SITE.

"He was jailed in Yemen and released after six months, and in 2011... joined AQAP," said the US-based group that monitors jihadist websites.

The United States is the only country that operates drones over war-torn Yemen.

In Washington, US Secretary of Defense Ashton Carter declined to confirm that Ansi had been the victim of a US strike.

"I cannot give you a specific answer on a particular strike," Carter said. "I will say that on the general question of AQAP, we will continue to apply pressure."