Jan 5 (Reuters) - Canadian Prime Minister Justin Trudeau is expected to announce as early as Monday that he will resign as Liberal Party Leader, The Globe and Mail reported on Sunday, citing three sources. The sources told the Globe and Mail that they don't know definitely when Trudeau will announce his plans to leave but said they expect it will happen before a key national caucus meeting on Wednesday. It remains unclear whether Trudeau will leave immediately or stay on as prime minister until a new leader is selected, the report said.