April 9 (Reuters) - The Keystone oil pipeline from

Canada to the United States remained shut on Wednesday following

an oil spill near Fort Ransom, North Dakota, and "return to

service" plans are being evaluated, its operator South Bow ( SOBO )

said.

The 4,327-km (2,689-mile) pipeline, a major conduit for

crude oil supply from Alberta to U.S. refineries in Illinois,

Oklahoma and along the U.S. Gulf Coast, was shut on Tuesday.

(Reporting by Brijesh Patel in Bengaluru; Editing by Sriraj

Kalluvila)