AMMAN — Police in Jordan sealed the headquarters of the Muslim Brotherhood in Amman on Wednesday, a senior figure in the Islamist movement said, as the authorities clamp down further on the kingdom’s most vocal opposition group.

The Brotherhood, which is close in ideology to its Egyptian namesake and has strong ties with the Palestinian movement Hamas, wants sweeping political reforms but stops short of calling for the overthrow of the monarchy.

Jordan’s authorities suppressed Arab Spring pro-democracy protests in which the mainstream Islamists played a prominent role, and human rights groups say that since then the kingdom has strongly curbed dissent.

Police acting on orders of the Amman governor evacuated staff and closed off the building, giving no reason for their actions, said senior Brotherhood member Jamil Abu Bakr.

Brotherhood spokesperson Badi Rafai later said the police closed another of its offices in the northern city of Jerash.

The movement, which has operated legally in Jordan for decades and has widespread grass-roots support in major urban centers, has scores of offices across the country.

Its political arm, the Islamic Action Front, is the kingdom’s largest opposition party and represents many disenfranchised Jordanians of Palestinian origin, who are in the majority in the population of seven million.