BELFAST (Reuters) - Northern Ireland's largest pro-British party on Thursday threatened to withdraw from the region's power-sharing government unless major changes are made within weeks to the terms of Britain's divorce deal with the European Union.

       In a speech in Belfast, Democratic Unionist Party leader Jeffrey Donaldson demanded the removal of most of the new trade barriers between the British province and the rest of the United Kingdom, and promised to block new measures due to implemented in the region's ports.

       "Within weeks it will be clear if there is the basis for the (Northern Ireland) Assembly and Executive to continue in this current mandate or whether there is a need for an Assembly election to refresh our mandate," Donaldson said.

       (Reporting by Amanda Ferguson; Writing by Conor Humphries; Editing by Kevin Liffey)