The office of President Francois Hollande has formally confirmed the death of a French hostage in Mali, one of six French citizens captured by al-Qaida's North African arm.

A statement from the president's office on Monday evening said an autopsy would be performed to learn the cause of death of Philippe Verdon once the body is transferred to France.

The media arm of Al-Qaida in the Islamic Maghreb, or AQIM, had said on Twitter in April that Verdon was dead after an unofficial announcement in march. Verdon had been captured in eastern Mali in November 2011 along with another French citizen. AQIM, al-Qaida's North African offshoot, is still believed to be holding five French hostages.

AQIM was one of three Islamic extremist groups who controlled northern Mali until a January French-led military intervention cut their stranglehold, killing extremists and scattering others to neighboring countries.

Verdon was known to be in ill health and there has been speculation that his death was related to pre-existing conditions. However, AQIM took credit for his death, saying in April that the fate of the remaining captives "is in the hands of French President Francois Hollande and the door is still open to find a just solution."

The presidential statement reiterated that "those responsible for the death of our countryman must be identified and judged."

France's Foreign Ministry had said that a body was found in northern Mali and that there was a "strong proability" it was Verdon. Tests to verify identity were carried out in Mali.