Former army chief-of-staff Sami Anan was being interrogated by the military prosecution on Tuesday over accusations including inciting against the army and forgery, two days after he announced his intention to run in Egypt's upcoming presidential elections.

Anan's campaign spokesman Mahmoud Refaat said on Twitter that the former military chief has been arrested and his son told local news website Youm 7 that his father has been detained for questioning by military prosecutors.

In an audio statement broadcast on state TV earlier on Tuesday, an army spokesman said Anan's announcement of his presidential bid amounts to "incitement against the military with the aim of driving a wedge between the armed forces and the Egyptian people."

"The armed forces would not tolerate the blatant legal violations committed [by Anan] which constituted a serious breach of the rules and regulations governing service of armed forces officers."

The statement said Anan announced his candidacy "without getting consent from the armed forces ... or following the required procedures to terminate his service."

It added that, in order to run for the late March election, the ex-military chief had forged official documents stating that his service with the military had ended.

Under Egyptian law, former military officials are required to end their service and receive authorization from the army before they can run for a political post.

According to a military law governing army officers, any army officer on a military reserve-list is subjected to the same regulations governing active-duty officers and can be called up by the army for national security reasons. In its statement, the army referred to Anan as still being on a call-up list.

The military has not yet issued an official confirmation of Anan's arrest, but said in the statement that "all legal procedures will be taken for violations and crimes committed [by Anan] that require his appearance before the relevant investigating bodies."

In a video announcing his presidential bid, Anan said he was running for president at a time of worsening living conditions, wrong policies and the state's failure to address major issues, while calling on the country's civil and military institutions to maintain neutrality toward all candidates.

The army's statement effectively ends Anan's candidacy for the presidency; his official presidential campaign said it has halted its activities "until further notice" following the army's announcement.

Anan served as chief-of-staff under ousted president Mohamed Morsi until the Islamist leader removed him from the post along with former defense minister at the time Mohamed Tantawy.

Egyptian President Abdel-Fattah El-Sisi said last week that he would run for a second term in office in the March vote, which he is widely expected to win. El-Sisi became president after winning a landslide victory in the 2014 vote almost a year after the overthrow of Morsi.

Another potential challenger to El-Sisi is human-rights lawyer Khaled Ali, who has also announced his intention to stand.

The presidential vote will be held on March 26-28, with a run-off vote scheduled on April 24-26 if no candidate wins a majority vote in the first round.