Iraq's health minister, who is aligned to a major Shiite militia, claimed Sunday that U.S. forces arrested seven of his personal guards in a surprise pre-dawn raid on his office. The reason for the alleged arrests was unclear.

Health minister Ali al-Shemari said the soldiers arrived at 3 a.m. Sunday, broke open doors inside the building leading to his office and hauled away the seven men, who were posted there as night guards.

CountryWatch: Iraq

There was no U.S. statement on he claim. However, a U.S. official, speaking on condition of anonymity because of the sensitivity of the case, said Iraqi forces with U.S. advisers searched the ministry after a tip from an Iraqi citizen and took five people into custody for further questioning.

"There was no legal warrant, there was no prior warning to the ministry, there was no reason to arrest them. It is a provocation," said al-Shemari, a Shiite aligned to the anti-U.S. radical cleric, Muqtada al-Sadr, who heads Iraq's biggest Shiite militia, the Mahdi Army.

"We demand that the government and the prime minister put an end to the American military operations," he told The Associated Press.

He said it appeared the seven men were arrested on false accusations made by unknown people. He did not elaborate.

The health minister was involved in a controversy when a senior health official from Diyala province, a Sunni, disappeared along with his secretary and two guards soon after a meeting with the minister in his office on June 12.

Sunnis claimed Dr. Ali al-Mahdawi, a member of the Sunni-based Iraqi Islamic Party, was kidnapped by Shiite militiamen, possibly the Mahdi Army. The minister, however, denied the allegations, saying he had interviewed al-Mahdawi for a more senior job, and that the official had left the building after the meeting.

The Mahdi Army, which is modeled along Lebanon's Hezbollah guerrillas, has emerged as a key force in the majority Shiite community. It launched two uprisings against the U.S. military in 2004 but adopted a low-profile on the advice of the Shiite clergy.

However, Sunni Arabs believe the militia is responsible for kidnapping and killing thousands of Sunnis since the Feb. 22 bombing of a Shiite shrine. Members of the militia also clashed with U.S. troops last month when they raided an al-Sadr stronghold in Baghdad.