CAIRO (Reuters) - An Egyptian court on Tuesday overturned decisions by a special committee to seize the assets of Muslim Brotherhood leaders, without saying which members or assets will be affected.

The Muslim Brotherhood's activities were banned last September and the government formed a committee a month later to manage the Brotherhood's funds and properties.

That committee froze the assets of many Brotherhood leaders as part of a crackdown that saw hundreds killed and thousands arrested after the army ousted President Mohamed Mursi of the Brotherhood in July 2013 following mass protests.

But on Tuesday, an administrative court said in a ruling seen by Reuters that 17 decisions made by the committee "ignored the provisions of the constitution and the law."

"A criminal court is the appropriate body to freeze funds and property, and preventing owners from accessing what is theirs cannot be done with an administrative decision," the ruling said.

The ruling did not identify which Brotherhood leaders' assets were covered under the 17 rulings it ordered halted, and only named the assets as "companies and business establishments and schools."

The court did not comment further and calls to a lawyer representing the Brotherhood were unanswered.

(Reporting By Shadi Bushra; Editing by Dominic Evans)