The influential brother of former Algerian President Abdelaziz Bouteflika and two generals once in charge of intelligence have been jailed while under investigation for plotting against the state, a military tribunal said Sunday.

A statement from the tribunal in Blida, south of Algiers, said the prosecutor appointed a judge to investigate the ex-president's young brother Said Bouteflika and generals Mohamed Mediene, known as Toufik, and Athmane Tartag.

They are being investigated for "plotting against the authority of the state" and "attacking the authority of the army," the statement said.

The three men were key figures during the era of Bouteflika, who resigned April 2 under pressure from the army and weeks of street protests after two decades in power.

A dramatic video aired on state television showed the three climbing the steps to the military tribunal.

Said Bouteflika, 61, was widely viewed in Algeria as the man at the center of a political system that enriched the oil-rich nation's industrialists while young Algerians suffered rates of high unemployment. He has been accused of usurping presidential powers after his brother's 2013 stroke.

Mediene was for 25 years in charge of military intelligence service DRS and one of Algeria's most powerful men until he was forced to resign in 2015.

Tartag headed the DSS state security service until last month, when he quietly stepped down after Bouteflika resigned.

Powerful army chief Ahmed Gaid Salah had publicly accused Toufik of plotting against the popular revolt and warned of legal action if he did not stop. He denounced Said Bouteflika as the head of the "gang" who ran the country.