The U.S. Postal Service announced Wednesday it is immediately embargoing mail to Britain because of a strike by postal workers in that country.

British postal deliveries are nearly at a halt, and 100 million pieces of undelivered mail have piled up in a week-old nationwide strike that idled more than half of the country's 180,000 postal workers.The embargo "was requested by the British postal administration because of its inability to handle any volume of mail," a Postal Service statement said.

Mail to Britain will be returned to senders. People who get such mail back can apply to their local post office for a refund of the postage.