Meet the new boss, same as the old boss.

CAIRO (NBC News) – Egypt’s embattled Muslim Brotherhood on Tuesday named a hardline new “general guide” hours after authorities arrested the movement’s senior leader, sources said.

The temporary appointment of Mahmoud Ezzat, a 69-year-old doctor, came amid a deepening crackdown on the Islamist movement of ousted President Mohammed Morsi.

“In the media, Ezzat has been personified as the Brotherhood’s ‘iron man,’ embodying its reputation for top-down decision-making,” U.S.-based think tank the Washington Institute said in an online bio.

Ezzat will be filling in for Mohammed Badie, 70, who was detained at an apartment in northeast Cairo early on Tuesday. His arrest followed the deaths of 25 police officers in a militant ambush in Sinai and a court ruling announcing the possibility that the jailed ex-President Hosni Mubarak could soon walk free from prison.

According to the Washington Institute, Ezzat “is currently a professor in Zagazig University’s College of Medicine, where his colleagues have included [former] President Morsi.”