Born in 1940 in the Batna region, 300 kilometres (186 miles) southeast of Algiers, he was 17 when he joined the National Liberation Army which for three years battled French colonial rule.

With Algeria's independence in 1962, he entered the ranks of the army before attending a Soviet military academy and scaling the ladder.

Gaid Salah successively commanded several military regions, before being appointed chief of staff of land forces in 1994, two years into the decade-long civil war between the Algerian army and armed Islamists.

In 2004, when he was about to be sent into retirement, Salah was tapped by Bouteflika to replace chief of staff Mohamed Lamari, who was from a faction that opposed to a second term for the president.

Now indebted to the president, General Gaid Salah became a loyal supporter of Bouteflika who in turn gave him the means to modernise the armed forces.

After returning from Paris in July 2013, where he spent 80 days in hospital following a stroke, Bouteflika gave him the added responsibility of deputy defence minister.

It was seen at the time as a title handed to the general in exchange for his support of Bouteflika for a fourth presidential term in 2014, in spite of his poor health.

General Gaid Salah also backed Bouteflika when he came under attack from the powerful DRS intelligence agency and its chief, General Mohamed Mediene, who was finally retired in 2015.

In recent months, he began by publicly supporting Bouteflika's bid for a fifth term.

But he abandoned the veteran leader after a string of manoeuvres from the presidency failed to quell public anger that had brought hundreds of thousands out onto the streets.

Last week he called for Bouteflika to either step down or be declared unfit to hold office.

On Tuesday he upped the pressure again by rejecting an announcement that the president would resign by the end of his mandate on April 28 and demanded the start of impeachment proceedings.

In a statement Gaid Salah called for "the immediate application of the constitutional procedure for removing the head of state from power".

Without naming anyone, Gaid Salah criticised "the stubbornness, the procrastination and the deviousness of certain individuals who are trying to make the crisis last and make it more complex with the only concern being their narrow personal interests".

He said the army's "sole ambition" was to "protect the people from a handful of people who have unduly taken over the wealth" of the country.