ABU DHABI ø Bahrain, alarmed by the prospect that Iranian operatives were directing unrest in the kingdom, has replaced the nation's leading security official with a military commander.

Over the weekend, the king ø in a move that Arab diplomatic sources said reflected a change in policy ø fired Interior Minister Mohammed Bin Khalifa Al Khalifa. Mohammed was replaced by Chief of Staff Maj. Gen. Rashid Bin Abdullah Bin Ahmed Al Khalifa. Mohammed has served as the kingdom's interior minister since 1974.

The king ordered Mohammed's resignation after a demonstration approved by authorities turned into a riot. The Shi'ite demonstration was meant to protest the U.S. military operations in the Iraqi Shi'ite cities of Karbala and Najaf, Middle East Newsline reported.

Witnesses said the protest turned violent when thousands of Shi'ite marchers encountered a line of anti-riot police. They said police fired tear gas when the marchers refused to turn back and at least 30 people were injured, many of them from rubber bullets and tear gas fired by officers.

"His Majesty the King emphasized that what happened between the police and demonstrators was saddening, pointing out that facts have to be found and those responsible should face the law," an official communique from the royal family. "His Majesty directed concerned authorities to launch an investigation of the incident."

Bahraini officials said the authorities have been concerned over the failure to stage peaceful protests in the kingdom. They said that virtually every authorized demonstration has turned into violence.

The demonstrations have included protests against the United States or for a greater voice in government. Officials said the repeated violence that resulted from these demonstrations have led to changes in the security establishment which could include a tougher law enforcement policy.

Officials said the king was angry over the failure of police to control the crowd and arrest inciters. They said four Shi'ite clergymen were injured in the clash.

"All concerned authorities in the country should observe and protect that right [of protest] as long as souls and properties are not jeopardized and peaceful means are not overstepped," Hamad said in a statement.

Arab diplomatic sources asserted that the outgoing interior minister was also blamed for failing to control the influx of Iranian operatives into Bahrain. They said prominent Shi'ites were believed to have facilitated entry to foreigners who later participated in Shi'ite unrest. Over the years, many of these foreigners were granted citizenship.

The new interior minister, Rashid, is 50 years old and appointed chief of staff in October 2001. Rashid was said to have advocated a preemptive approach toward Shi'ite agitators. For his part, Mohammed was appointed deputy head of the ruling family council.

Hamad authorized Rashid, promoted to the rank of lieutenant general, to improve the security forces in Bahrain. He said the ministry and security services maintained a vital role in the kingdom.