"Bahraini security forces broke up a cell that had been plotting terrorist acts ... targeting the kingdom's national interests and endangering the lives of innocent citizens," said the spokesman, quoted by the official BNA news agency.

It was the first time the small Gulf kingdom has announced the arrest of Bahraini "terrorists" on its soil since the September 11, 2001 deadly attacks against the United States.

Mukhtar al-Bakri, a U.S. citizen of Yemeni descent allegedly connected to the al-Qaeda network, gave himself up to U.S. authorities in Bahrain in September last year and was transferred to the United States.

Security forces "seized arms and ammunition" which members of the cell "planned to use to carry out terrorist acts against the security of the country and its citizens," the spokesman said.

The five suspects are were arrested three days ago, a senior Bahraini official said, requesting anonymity. Pistols, machineguns and ammunition were found in their possession, he added.

Investigations were under way to "establish if the cell is linked to groups inside or outside Bahrain," the official added, in a reference to the al-Qaeda organization of Saudi-born Osama bin Laden.

Terror charges were in the past mostly leveled at members of the majority Shiite Muslim community in Sunni-ruled Bahrain. The identification of the cell members as Sunnis appeared meant to point to a connection with Bin Laden supporters.

The official spokesman identified the members of the cell as Mohieddin Mahmud Mohieddin Khan, born in Lebanon in 1961; Bassam Abderrazzak Abdullah Bukhua, born in 1970; Bassam Yussef Abdelkarim Ali, 1956; Issa Abdullah Abderrahman al-Baluchi, born in the Saudi city of al-Khobar in 1972; and Jamal Hilal Mohammad al-Baluchi, 1965.

Bahrain, a key Washington ally in the Gulf, is home to the American Fifth Fleet, and hosts about 1,000 U.S. military personnel.

The United States and Britain have massed troops and equipment in the region for a possible military strike on Iraq.