By Dave Sherwood and Allison Lampert HAVANA/MONTREAL, Feb 9 (Reuters) - Air Canada said on Monday it is suspending flights to Cuba, which warned it was running out of jet fuel, as the U.S. tightens its grip on the communist-run nation's oil supply by blocking shipments from Venezuela.

Air Canada is suspending its service to Cuba due to an ongoing shortage of aviation fuel on the island.

The Foreign Office, meanwhile, has issued a new warning about power cuts across the island, some lasting more than 24 hours, due to a lack of fuel for generators.