Jordan has announced a sweeping ban on the Muslim Brotherhood that could include shutting down the country’s largest opposition party, after accusing the Islamist group of planning attacks.

The Islamic Action Front, a political party linked to the regionwide Brotherhood, won the most seats in parliamentary elections held last year against the backdrop of mass protests against Israel over its war with Hamas.

The monarchy banned the Muslim Brotherhood a decade ago but officially licensed a splinter group and continued to tolerate the Islamic Action Front while restricting some of its activities. It was not immediately clear how far the latest ban would go.

Police surrounded and searched the Islamic Action Front’s headquarters after Wednesday’s announcement and seized several boxes of documents.

The Interior Ministry said the Muslim Brotherhood is now considered an illegal organization and announced a ban on any political activities related to the group and the closure of its offices. It said efforts to confiscate the group’s assets would be accelerated.