WASHINGTON (Reuters) - The Canadian embassy in Washington was evacuated briefly on Friday because of a suspicious letter, forcing out employees for more than an hour, officials said.

U.S. Secret Service and local emergency responders investigated the incident but found nothing dangerous.

"It was found to be non-hazardous," Secret Service spokesman Max Milien said of the letter.

Embassy spokesman Chris Plunkett said the embassy's 325 employees were evacuated at around 9:30 a.m. EDT (1330 GMT) after a suspicious letter was found in the mail room.

Workers spilled onto Pennsylvania Avenue, a major artery that leads to the White House just 1.5 miles away, which was partially blocked off before the all-clear was given.

Plunkett said embassy staff were allowed back in at around 10:35 a.m. (1435 GMT).

Officials gave no other details about the contents of the letter or who sent it.

(Reporting By Ian Simpson and Susan Heavey; Editing by Vicki Allen)