BASRA, Iraq — British armored vehicles broke down the walls of the central jail in this southern city Monday and freed two British soldiers, allegedly undercover commandos arrested for shooting two Iraqi policemen, witnesses said. But London said the two men were released as a result of negotiations.

The different versions of events came on a chaotic day that raised questions about how much sovereignty Iraqi authorities really were granted when the U.S.-led Coalition Provision Authority handed over power to an interim Iraqi government in the summer of 2004.

The arrests of the two British soldiers Monday appeared to have been the first real and public test of how far that sovereignty extends. There have been no known incidents of Iraqi authorities arresting U.S. soldiers operating in the Iraqi heartland.

Mohammed al-Waili, the governor of Basra province, condemned the British for raiding the prison, an act he called "barbaric, savage and irresponsible."

"A British force of more than 10 tanks backed by helicopters attacked the central jail and destroyed it. This is an irresponsible act," al-Waili said, adding that the British force had spirited the prisoners away to an unknown location.

Aquil Jabbar, an Iraqi television cameraman who lives across the street from the Basra jail, said about 150 Iraqi prisoners fled as British commandos stormed inside and rescued their comrades.

Late Monday, the Ministry of Defense in London said the two British soldiers were freed after negotiations. A spokesman said he had no information suggesting they were freed as a result of overt military action, but he stopped short of denying reports that British armor crashed through the walls of the jail.

According to the BBC, defense officials insisted they had been talking to the Iraqi authorities to secure the release of the men but acknowledged a wall was demolished as British forces tried to "collect" the two prisoners.

While the Shiite-dominated south of Iraq, where 8,500 British troops are based, has been far quieter than Sunni regions to the north, Britons have come under increasingly frequent attacks in recent weeks. The British military has reported 96 deaths since the war began in 2003.

That compares with the deaths of 1,899 Americans who are stationed nearer the violent insurgent regions around Baghdad and stretching west to the Syrian border.

The latest violence in the oil city of Basra, 340 miles south of the capital, began early Monday when local authorities reported arresting the two Britons, described as special forces commandos dressed in Arab clothing, for allegedly shooting two Iraqi policemen, one of whom died.