MANAMA, Bahrain (AP) — A series of bomb blasts in Bahrain’s capital killed two people Monday, authorities said, a sign that some factions within the opposition may be increasingly turning to violence in the nearly 21-month uprising against the Gulf nation’s Western-backed rulers.

The apparently coordinated string of five explosions in Manama — described by officials as "terrorism" — comes less than a week after Bahrain banned all protest gatherings in attempts to quell the deepening unrest in the strategic kingdom, which is home the U.S. Navy’s 5th Fleet.

But clashes have not eased, including crowds pelting three police stations with firebombs early Sunday. More than 55 people have been killed Bahrain’s unrest since February 2011 as the nation’s majority Shiites press for a greater political voice in the Sunni-ruled island nation.

In Monday’s violence, two Asian men were killed and a third person injured as at least five homemade explosive devices were detonated, the Interior Ministry said. One man died after kicking the bomb and triggered the explosion and the other died from injuries in a separate blast, officials said. Like all Gulf Arab countries, Bahrain has a large South Asian community of expatriate workers.

The official Bahrain News Agency described the blasts as an "act of terrorism."

Anti-government factions in Bahrain have used homemade bombs in the past, including a blast that killed a policeman last month in a mostly Shiite village. But the latest attack suggests an expanding campaign of violence because of the scope of the bombings and their placement scattered throughout the heart of the capital, including one area of restaurants and nightlife popular with Westerners.

On Wednesday, foreign ministers from the Gulf Cooperation Council plan to meet in Bahrain to discuss regional issues, including Bahrain’s tensions and growing clashes in Kuwait between security forces and an opposition led by Islamists.

Bahrain’s Western allies have urged for renewed efforts at dialogue to ease the crisis, but opposition groups insist that talks cannot move forward unless the monarchy is willing to make greater concessions to loosen its hold on the country’s affairs. Bahrain’s leaders have so far made reforms that include transferring more oversight powers to the elected parliament.

Shiites comprise about 70 percent of Bahrain’s 525,000 citizens, but claim they face systematic discrimination such as being blocked from top political and security posts.

Last week, the U.S. State Department issued unusually harsh criticism against ally Bahrain after its decision to outlaw all public demonstrations. Previously, officials in Bahrain had permitted some protest marches, but most clashes have occurred outside the authorized rallies.

"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," said State Department spokesman Mark Toner.