Canadian airlines suspended flights to Cuba on Monday after the island warned it was running out of jet fuel amid U.S. efforts to block oil shipments from Venezuela.

Air Canada said aviation fuel is expected to be unavailable at Cuban airports starting Tuesday, prompting it and smaller carriers WestJet and Air Transat to cancel flights.

A notice to pilots said the fuel shortage could last from February 10 through March 11, contradicting earlier assurances from Cuban officials that air travel would not be affected.

Cuba’s Aviation Corporation issued a statement emphasizing operational reliability but did not address the fuel shortage or cancellations, Reuters has reported.

The Cuban government did not immediately respond to requests for comment.