WASHINGTON —

WASHINGTON (AP) The Obama administration on Wednesday denounced in unusually harsh terms a ban on public demonstrations imposed by Bahrain, a key American ally in the Gulf that is home to the U.S. Navy’s 5th Fleet.

The State Department said Washington is “deeply concerned” by the ban, which it said violates freedom of assembly, association and expression. Spokesman Mark Toner said the move, which was announced on Tuesday, raises questions about Bahrain’s promises to reform and he urged authorities to uphold fundamental human rights.

“The decision to curb these rights is contrary to Bahrain’s professed commitment to reform and will not help advance national reconciliation nor build trust among all parties,” he said.

He said the government should work with the opposition to address complaints that have sparked months of unrest. He also called on the opposition to renounce provocation and violence, such as recent attacks against security forces, which he said were “deeply troubling.” And, he urged both sides to restore confidence and stability.

Violence undermines efforts to reduce tensions and rebuild trust, he said, adding: “We urge the government of Bahrain to take steps to build confidence across Bahraini society and to begin a meaningful national dialogue with the political opposition.”

The ban is the most sweeping attempt to quash the kingdom’s anti-government uprising since martial law rules were in effect during the early months of unrest last year. It sharply increases pressure on political groups from Bahrain’s Shiite Muslim majority, which has led the protests seeking a greater political voice in the Sunni Muslim-ruled nation.

Shiites comprise about 70 percent of Bahrain’s 525,000 citizens, but claim they face systematic discrimination such as being denied top political and security posts. The Sunni monarchy has made a series of concessions including giving more powers to the elected parliament but opposition groups say the reforms do little to loosen the ruling family’s hold on power.

More than 50 people have been killed in Bahrain’s unrest since February 2011. Among them were two policemen who died this month from injuries suffered in attacks by firebombs and explosives.

Bahrain’s interior minister stressed Wednesday that the ban is only temporary and will be rescinded once security and stability are restored.