The order is the result of a planned security check rather than a new threat to aviation — and a sign of heightened concerns about the vulnerability of cargo in the wake of an Al Qaeda plot to disguise bombs as toner cartridges shipped on freight flights from Yemen.

The Department for Transport in Britain said that “following careful consideration, the department has restricted the number of sites in the U.K. at which U.P.S. Ltd. are permitted to screen air cargo until it has satisfied current security requirements.”

It gave no details of the security issues and did not identify the locations involved. No other air freight companies were mentioned in the statement.

U.P.S., which is based in Atlanta, said the restrictions were the result of a security review rather than any specific threat.

A U.P.S. spokeswoman, Susan Rosenberg, said six of the company’s British package-screening facilities were still operating, its main air hub at East Midlands Airport in central England was open and its planes were still flying to and from Britain.

She would not say how many facilities had been shut, how many packages were being disrupted or whether packages being sent to Britain as well as those leaving the country were affected, citing the need to preserve secrecy around security arrangements.

The United States has not taken similar measures, because U.P.S. Ltd. U.K. is a separate subsidiary of U.P.S. and is not regulated by the United States government, an American Transportation Security Administration official said. The official said the United States already had “stringent security protocols” in place for air cargo security.

U.P.S. told customers Friday that some shipments from Britain were being delayed. It said “areas of concern” were found during a government review of “U.P.S. procedures and employment documentation related to security.”

The company said some facilities had been temporarily “taken offline,” leading to delays in package movements.

“U.P.S. has activated contingency plans, communicated with customers and expects service levels to return to normal early next week,” the company said. “U.P.S. continues to work with all agencies around the world to maintain and enhance security and to balance necessary protections with the free flow of commerce, just as we have always done.”

Article source: http://www.nytimes.com/2011/06/18/business/18ups.html?partner=rss&emc=rss