The Egyptian Armed Forces launched an investigation against their former chief of staff Sami Annan on Tuesday, claiming he had forged official documents that would allow him to run for president in March.

Three of Annan's top aides also reported he was detained by the military.

The former general announced his intent to run for president on Friday, posing a challenge to the current president and fellow former general Abdel-Fattah el-Sissi. The president took power in the 2013 military coup and is still backed by the army.

Read more: El-Sissi gears up for re-election in Egypt

Sami Annan (left) served as Chief of Staff until then-President Mohammed Morsi ordered him into retirment

On Tuesday, top army officials said Annan had failed to follow regulations before announcing his candidacy, which require officers to formally end their service and ask for permission from the central command.

Annan is now suspected of forging the required documents, but also of "inciting against the Egyptian army with the aim of driving a wedge between the armed forces and the Egyptian people."

The military also said it would "not overlook the blatant legal violations (Annan) has committed" against the laws of military service.

'Election' with one candidate?

Annan is not the first presidential candidate to give up his run after coming under pressure from institutions backing el-Sissi. Former lawmaker Mohammed Anwar Sadat previously announced he was dropping out of the race, partly out of fear for the safety of his supporters.

Read more: UAE deports Egyptian presidential hopeful Ahmed Shafiq

Earlier this month, former Prime Minister Ahmed Shafiq said he was dropping out due to his prolonged absence from Egypt. Shafiq also served as air force general before fleeing to the United Arab Emirates in 2012. His return in 2017 sparked criticism from state-aligned media.

Read more: Egypt's ex-PM Ahmed Shafix will not run for president

The only remaining challenger to el-Sissi, human rights activist Khaled Ali, might also be pushed from the race over a lewd hand gesture he made in September, after winning an earlier legal case.

dj/msh (dpa, AP, AFP, Reuters)