Egypt State TV/AP Photo

BY MOLLY HUNTER and ADAM MAKARY

CAIRO - The Muslim Brotherhood's Supreme Guide, Mohammed Badie, was arrested overnight, according to security sources, as Egypt's interim government continues its rampant crackdown on the group.

Badie, 70, was reportedly arrested in a residential apartment near Raba'a Al Adaweya in Cairo's eastern Nasr City. More than 1,000 people were reportedly killed at Raba'a last Wednesday, when security forces dispersed a massive sit-in filled with supporters of ousted president Mohamed Morsi. On Friday, 179 people were killed in clashes near Cairo's Ramses Square including Badie's 38-year-old son, Ammar Badie.

Security forces tell ABC News that Nasr City residents tipped them off to Badie's location Monday night. Following his arrest, t he private channel ON TV showed video of Badie's arrest. ABC News obtained a photograph of Badie in his pajamas flanked by two authorities after his arrest.

The Brotherhood announced this morning that Dr. Mahmoud Ezzat has been appointed acting general guide in Badie's absence. Referred to as the Brotherhood's " iron man ," Ezzat served as the deputy supreme guide under Badie.

A warrant for Badie's arrest has been out for weeks and he joins a slew of top Brotherhood officials already detained, mostly accused of inciting violence that led to the deaths of protesters. He is expected to stand trial next month alongside Khairat el-Shater, the Brotherhood's powerful deputy leader and chief financial backer, currently being held in Cairo's Tora prison.

Earlier Monday, the interim government extended the detention of ousted president Mohamed Morsi, who has been held in an undisclosed location since the July 3 coup.

As the Brotherhood leadership disappears off the streets, the group's ability to mobilize its supporters in the country's capital has been called into doubt. Following the country's bloodiest day in modern history, the Brotherhood announced seven days of protests for a "Week of Departure." But so far, massive crowds have failed to manifest.

No protests were called on Monday and the usually hyper active Twitter feed of Brotherhood spokesman, Gehad El Haddad fell silent. As the Brotherhood regroups, it may only be the calm before the next storm.