Most mail to Canada must bear the complete name and address of both sender and recipient or it won't be allowed into the country, the U.S. Postal Service (search) said Wednesday. The tighter addressing requirements are in response to increased security.

Even such sender or recipient identifications as "Grandma" or "Aunt Ruth" can result in mail being rejected, the agency said.

All mail, except post cards, that does not show the complete name and address of sender and recipient — in Roman letters and Arabic numerals — is being denied entry.

Canada Post (search) spokesman John Caines said that Canadian customs officials have become increasingly vigilant about enforcing the requirement that all international mail have a complete address for both the sender and recipient.

U.S. postal officials said addresses on mail to Canada should be printed in ink or typewritten in capital letters, and the last line of the address must show only the country name, written in full, and in capital letters. When a Canadian postal delivery zone number is included in the address, mailing requirements allow that number to appear as the last line of the address.

Mailers must also fill out necessary customs forms specifying the contents of parcels. General descriptions such as "gift" or "present" are not acceptable.

U.S. officials said Canadian Customs (search) offices are reporting a backlog of incoming postal items with incomplete or inaccurate information. Canadian officials say these items will be returned to their points of origin as soon as practical.

Mail enters Canada at three points, Montreal, Toronto and Vancouver. Caines said the Vancouver office is experiencing a backlog of parcels which have been help up because of staffing problems.