Four U.S. Embassy workers driving through Baghdad were stopped and detained by Iraqi security forces for two hours Thursday, a day after the embassy warned that some American citizens working here had been held for days over “discrepancies in permits and paperwork.”

The tensions come more than three weeks after the U.S. military left a country that has since been rocked by a political crisis and spectacular bombings. Baghdad’s governor was quoted on an Iraqi news Web site Thursday as calling the embassy workers’ behavior “suspicious.” But an embassy spokesman played down the detention, saying the staff members were served tea as security officers checked their paperwork.

“The identities were verified, and they were released,” said the spokesman, Michael McClellan.

Other U.S. citizens have apparently been held much longer.

“Detentions often last 24-96 hours or more,” the U.S. Embassy said in a statement posted on its Web site. “The Embassy’s ability to respond to situations in which U.S. citizens are arrested or otherwise detained throughout Iraq is limited, including in and around Baghdad.”

This was supposed to be the diplomatic phase of the U.S.-Iraq strategic partnership, with the American presence anchored by State Department workers inside the sprawling U.S. Embassy in the fortified Green Zone.

McClellan would not say what the four staff members were doing, calling it “routine movement.” Diplomats have to leave the Green Zone to visit certain government agencies and businesses, in addition to other Iraqi cities.

McClellan said that embassy staffers always travel with security personnel.

Two Iraqi news Web sites, and, quoted Baghdad Gov. Salah Abdul Razzaq as saying that the Americans told Iraqi officers they were in the area to check on security.

According to Agence France-Presse, the governor said that the group comprised two men and two women driving a BMW with local license plates, rather than diplomatic registration, and that all were armed and wearing flak jackets. Security forces stopped the group, checked their ID badges and “found them suspicious,” Razzaq told AFP, adding that the group had been stopped at 9 a.m. in a central Baghdad neighborhood.

The Post could not reach the governor for comment.

In the warning notice posted on its Web site, the U.S. Embassy said that “the Government of Iraq is strictly enforcing immigration and customs procedures, to include visas and stamps for entry and exit, vehicle registration, and authorizations for weapons, convoys, logistics, and other matters,” adding, “Rules and procedures may be subject to frequent revisions, and previous permissions may be deemed invalid.”

The moves come as Prime Minister Nouri al-Maliki has used speeches and interviews to celebrate Iraq’s full independence as a nation in the wake of the U.S. departure. They also follow a recent report by the World Bank ranking Iraq as the 164th most difficult nation in the world in which to do business, out of 183 countries.

Special correspondent Asaad Majeed contributed to this report.