CAIRO -- A top aide of ousted President Hosni Mubarak's was arrested Thursday in a corruption investigation, the highest ranking ex-official to be jailed since Egypt's longtime ruler stepped down in February under pressure from a popular uprising.

Former presidential chief of staff Zakariya Azmi is accused of using his powerful position to amass a fortune, prosecutor Assem al-Gawhari told the state-run news agency. He said Azmi will be jailed for 15 days.

Egyptian prosecutors have filed charges and handed travel bans and jail time to many former top-ranking officials since demonstrators finally toppled Mubarak's three-decade rule Feb. 11 after 18 days of protests.

Many Egyptians consider the prosecutions one of their revolution's key achievements. But they worry that Egypt's governing military council hasn't allocated enough resources to speedily chase down former Mubarak cronies -- and they say prosecutors have not filed any charges against the former ruler either. Their criticisms have only grown louder as they learn the extent of alleged back-room deals that plundered their public assets.

Azmi's arrest may partly allay those worries. He was considered Mubarak's most trusted right-hand man, an influential mover within the old ruling party.

His arrest follows that of Egypt's former housing minister, Mohammed Ibrahim Suleiman, on Wednesday. He will also be held for 15 days on suspicion he was involved in the illegal sale of state lands for cut-rate prices.