WASHINGTON (AP) -- President-elect Donald Trump on Thursday voiced his support for the dockworkers union before their contract expires next month at Eastern and Gulf Coast ports, saying that any further "automation" of the ports would harm workers.

The incoming president posted on social media that he met Harold Daggett, the president of the International Longshoreman's Association, and Dennis Daggett, the union's executive vice president.

"I've studied automation, and know just about everything there is to know about it," Trump posted. "The amount of money saved is nowhere near the distress, hurt, and harm it causes for American Workers, in this case, our Longshoremen. Foreign companies have made a fortune in the U.S. by giving them access to our markets. They shouldn't be looking for every last penny knowing how many families are hurt."

The International Longshoremen's Association has until Jan. 15 to negotiate a new contract with the U.S. Maritime Alliance, which represents ports and shipping companies.

At the heart of the dispute is whether ports can install automated gates, cranes and container-moving trucks that could make it faster to unload and load ships. The union argues that automation would lead to fewer jobs, even though higher levels of productivity could do more to boost the salaries of remaining workers.

The Maritime Alliance said in a statement that the contract goes beyond ports to "supporting American consumers and giving American businesses access to the global marketplace - from farmers, to manufacturers, to small businesses, and innovative start-ups looking for new markets to sell their products."

"To achieve this, we need modern technology that is proven to improve worker safety, boost port efficiency, increase port capacity, and strengthen our supply chains," said the alliance, adding that it looks forward to working with Trump.

In October, the union representing 45,000 dockworkers went on strike for three days, raising the risk that a prolonged shutdown could push up inflation by making it difficult to unload container ships and export American products overseas.

The issue pits an incoming president who won November's election on the promise of bringing down prices against commitments to support blue-collar workers along with the kinds of advanced technology that drew him support from Silicon Valley elite such as billionaire Elon Musk.

Trump sought to portray the dispute as being between U.S. workers and foreign companies, but advanced ports are also key for staying globally competitive. China is opening a $1.3 billion port in Peru that could accommodate ships too large for the Panama Canal.

There is a risk that shippers could move to other ports, which could also lead to job losses. Mexico is constructing a port that is highly automated, while Dubai, Singapore and Rotterdam already have more advanced ports.

Instead, Trump said that ports and shipping companies should eschew "machinery, which is expensive, and which will constantly have to be replaced."

"For the great privilege of accessing our markets, these foreign companies should hire our incredible American Workers, instead of laying them off, and sending those profits back to foreign countries," Trump posted. "It is time to put AMERICA FIRST!"

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