FILE PHOTO: A commercial truck with a Canada, United States and Mexico flag on its side is seen crossing over the Ambassador Bridge into Windsor, Ontario from Detroit, Michigan U.S. August 29, 2018. REUTERS/Rebecca Cook/File Photo

OTTAWA (Reuters) - The United States and Canada have reached a framework deal to update the North American Free Trade Agreement, a Canadian source said late on Sunday.

It involves offering more dairy access to U.S. farmers, as well as Canada agreeing to a side-letter arrangement effectively capping automobile exports to the United States, the source said.