CAIRO -- Egyptian security forces raided the headquarters of the newspaper of the Muslim Brotherhood's political arm, confiscating equipment and sealing off the building, the paper's staff said Wednesday. The move against the Freedom and Justice newspaper, affiliated with the party of the same name, was the latest in a series of escalating measures by Egyptian authorities against the Brotherhood. The newspaper had circulated clandestinely in recent weeks, after other media outlets linked to the movement were shut down. But its reporters said they had continued to work up until the raid, and demanded to be allowed to do so again. "What happened is thuggery on the part of security forces," the staff said in a statement in which they asked the state press syndicate to rally to their defense. The Brotherhood is the main backer of Islamist President Mohamed Morsi, who was deposed in a military-led coup on July 3. The following month, police broke up large-scale sit-ins by Morsi's supporters, killing as many as 1,000 people. Most of the Brotherhood's top leaders, including Morsi, are behind bars, together with hundreds of rank-and-file members. Still more are in hiding. On Monday, a court in Cairo banned all activities by the Brotherhood and ordered its assets confiscated, paving the way for a wide-ranging crackdown on the many groups associated with the movement. Brotherhood officials said Tuesday they would appeal that ruling, and the government said it would not move ahead with a wholesale dissolution of the organization until that appeal is considered.