AMMAN – Jordan announced Wednesday a sweeping ban on the Muslim Brotherhood that could include shutting down the country’s largest opposition party, after accusing the 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.

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

Police surrounded the party’s headquarters after Wednesday’s announcement and were searching it.

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.

“It has been proven that members of the group operate in the dark and engage in activities that could destabilize the country,” the ministry said. “Members of the dissolved Muslim Brotherhood have tampered with security and national unity, and disrupted security and public order.”

It said a son of one of the group’s leaders had joined others in trying to manufacture and test explosives to be used against security forces, without providing names or further details.

Last week, Jordan said it had arrested 16 people accused of manufacturing short-range missiles, possessing explosives and automatic weapons, concealing a ready-to-use missile, and illegally recruiting and training people.

The government said the accused belong to what it called “unlicensed groups,” referring to the Muslim Brotherhood. The Brotherhood denied the allegations and said it was committed to Jordan’s security.

Jordan is a close Western ally that has long been seen as a bastion of stability in the volatile Middle East. It borders Israel, the occupied West Bank, Syria, Jordan, Iraq and Saudi Arabia, and is hosting hundreds of thousands of refugees from multiple conflicts.

The Muslim Brotherhood was established in Egypt nearly a century ago and has branches across the world. Its leaders say it renounced violence decades ago and seeks Islamic rule through elections and other peaceful means. Critics, including autocratic governments across the region, view it as a threat.