(Reuters) -The Trump administration's order to halt work on a major wind farm under construction off the coast of Rhode Island threatens grid reliability and jobs, energy and labor officials said on Monday.

ISO New England, which operates the grid in six states, and North America's Building Trades Unions made those criticisms in statements after President Donald Trump's Interior Department on Friday abruptly ordered work to stop on the Revolution Wind project, which is 80% complete, citing unspecified national security concerns.

Shares of project developer Orsted, which is based in Denmark, sank to record lows on Monday.

"The ISO is expecting this project to come online and it is included in our analyses of near-term and future grid reliability," the grid operator for 15 million people said. "Delaying the project will increase risks to reliability."

NABTU, an alliance of 14 building and construction unions, said the order affected the jobs of 1,000 members.

"A 'stop-work order' is the fancy bureaucratic term, but it means one thing: throwing skilled American workers off the job after they've spent a decade training, building, and delivering," NABTU President Sean McGarvey said in a statement.

Revolution Wind, which is off the coast of Rhode Island, was scheduled to be completed next year and was expected to produce enough electricity to power 350,000 homes in Rhode Island and Connecticut.

The governors of those states, both Democrats, have also criticized the Interior Department move, saying it jeopardized jobs, energy affordability and electricity reliability.

An Interior Department spokesperson had no comment on the stop-work order on Monday. The move was revealed in a letter to Orsted late on Friday.

President Donald Trump, a Republican, has repeatedly criticized wind energy as ugly, unreliable and expensive. His administration has taken several steps to rein in wind development.