MANAMA, BAHRAIN - The Bahraini military fired live ammunition at anti-government demonstrators Friday, inflicting casualties on marchers who tried to reach the scene of a deadly crackdown the day before, witnesses said.

Hundreds of predominately Shiite anti-government protesters were marching toward a public hospital following a funeral for a demonstrator who was killed Thursday when riot police overran a protest encampment at Pearl Square. The procession then suddenly diverted toward the square, which protesters had sought to turn into this tiny kingdom's equivalent of Cairo's Tahrir Square, the epicenter of demonstrations that toppled President Hosni Mubarak in Egypt last week.

President Obama said Friday he was "deeply concerned by reports of violence in Bahrain, Libya and Yemen," as he condemned harsh government responses to peaceful protests. In a statement issued by the White House while he was visiting the West Coast, Obama urged the three countries "to show restraint in responding to peaceful protests, and to respect the rights of their people."

In Britain, the Conservative-led coalition government on Friday decided to revoke a series of weapons sale licenses to Bahrain and Libya after coming under heavy criticism for striking such deals with Arab governments that are now cracking down on protesters. The "urgent" policy review came after London approved recent sales to Bahrain of 250 tear gas canisters, crowd-control ammunition and equipment for use in aircraft cannons, assault rifles and other weapons.

At Pearl Square, army armored personnel carriers had been parked all day to secure the area and prevent protesters from reaching the site.

"The APCs came, three or four of them, and started firing shots," Mazen Mahdi, a Bahraini photojournalist who was accompanying the procession, said in an interview. "The first was a warning shot in the air. But after that, they just opened fire at the people."

Mahdi described the shooting as live fire from machine guns. After about 30 minutes, the police, who had retreated to let the APCs approach, returned and fired tear gas, dispersing all demonstrators from the area.

Mahdi said he saw ambulance crews being prevented from reaching the site. "They shot at the ambulances when they came in," he said.

There was no statement from the military, but an official at the Interior Ministry sent a text message to Bahrainis Friday night urging them to stay indoors.

As of around 8 p.m., there were approximately 50 riot police cars on the Pearl Square roundabout, a resident who lives above the square said. "We did hear gunshots fired," the resident, who declined to be identified by name, said by telephone.

At the main public hospital, Salmaniya, three people were undergoing surgery for serious head injuries, and many more were arriving with less serious wounds, witnesses said. CNN reported that four people were killed, but that could not immediately be confirmed.

Witnesses said the Salmaniya hospital was overwhelmed with wounded and that casualties were being diverted to private hospitals around the capital.