MANAMA, Bahrain — Soldiers opened fire today on thousands of protesters defying a government ban and streaming toward the landmark square that had been the symbolic center of the uprising to break the political grip of the Gulf nation’s leaders.

Officials at the main Salmaniya hospital said at least 50 people were injured, some with gunshot wounds. Some doctors and medics on emergency medical teams were in tears as they tended to the wounded. X-rays showed bullets still lodged inside victims.

“This is a war,” said Dr. Bassem Deif, an orthopedic surgeon examining people with bullet-shattered bones.

Protesters described a chaotic scene of tear gas clouds, bullets coming from many directions and people slipping in pools of blood as they sought cover. Some claimed the gunfire came from either helicopters or sniper nests, a day after riot police swept through the protest encampment in Pearl Square, killing at least five people and razing the tents and makeshift shelters that were inspired by the demonstrators in Cairo’s Tahrir Square.

An Associated Press cameraman saw army units shooting anti-aircraft weapons, fitted on top of armored personnel carriers, above the protesters, in apparent warning shots and attempts to drive them back from security cordons about 200 yards from the square.

Then the soldiers turned firearms on the crowd, one marcher said.

“People started running in all directions and bullets were flying,” said Ali al-Haji, a 27-year-old bank clerk. “I saw people getting shot in the legs, chest, and one man was bleeding from his head.”

“My eyes were full of tear gas, there was shooting and there was a lot of panic,” said Mohammed Abdullah, a 37-year-old businessman taking part in the protest.

The clash came hours after funeral mourners and worshippers at prayers today called for the toppling of the Western-allied monarchy in the tiny island nation that is home to the U.S. Navy’s 5th Fleet, the centerpiece of the Pentagon’s efforts to confront Iranian military influence. Some members of Bahrain’s Sunni ruling system worry that Shiite powerhouse Iran could use Bahrain’s majority Shiites as a further foothold in the region.

The White House has expressed “strong displeasure” about the rising tensions in Bahrain.

Day by day, the crisis in Bahrain has deepened.

The cries against the king and his inner circle – at a main Shiite mosque and at burials for those killed in Thursday’s crushing attack – reflect a sharp escalation of the political uprising, which began with calls to weaken the Sunni monarchy’s power and address claims of discrimination against the Shiite majority.

The mood, however, has turned toward defiance of the entire ruling system after the brutal crackdown on a protest encampment in Bahrain’s capital, Manama, which put the nation under emergency-style footing with military forces in key areas and checkpoints on main roads.

“The regime has broken something inside of me. … All of these people gathered today have had something broken in them,” said Ahmed Makki Abu Taki at the funeral for his 23-year-old brother, Mahmoud, who was killed in the pre-dawn sweep through Pearl Square. “We used to demand for the prime minister to step down, but now our demand is for the ruling family to get out.”

At a Shiite mosque in the village of Diraz, an anti-government hotbed, imam Isa Qassim called the Pearl Square assault a “massacre” and thousands of worshippers chanted: “The regime must go.”

In a sign of Bahrain’s deep divisions, government loyalists filled Manama’s Grand Mosque to hear words of support for the monarchy and take part in a post-sermon march protected by security forces. Many arrived with Bahraini flags draped over the traditional white robes worn by Gulf men. Portraits of King Hamad bin Isa Al Khalifa were distributed.

“We must protect our country,” said Adnan al-Qattan, the cleric leading prayers. “We are living in dangerous times.”

He denounced attempts to “open the doors to evil and foreign influences” – an apparent reference to suspicions that Iran could take advantages of any gains by Bahrain’s Shiites, who account for about 70 percent of the population.

The pro-government gathering had many nonnative Bahrainis, including South Asians and Sunni Arabs from around the region. Shiite have long complained of policies giving Sunnis citizenship and jobs, including posts in security forces, to offset the Shiite majority.

Outside a Shiite village mosque, several thousand mourners gathered to bury three of the men killed in the crackdown. The first body, covered in black velvet, was passed hand to hand toward a grave as it was being dug.

Amid the Shiite funeral rites, many chanted for the removal of the king and the entire Sunni dynasty that has ruled for more than two centuries in Bahrain – the first nation in the Gulf to feel the pressure for changes sweeping the Arab world.