US President Donald Trump defended the rapid buildout of massive data centres at a rally in Ohio on Saturday. He warned that turning the projects away would hand an advantage to China in the race for artificial intelligence.

“There’s so much money to be made for Ohio. You can’t just turn them off. They’ll go to China,” Trump told supporters at Butler High School in Vandalia, near Dayton. The rally was held to boost Senator Jon Husted’s Senate campaign and gubernatorial candidate Vivek Ramaswamy ahead of next month’s midterms.

Trump backed legislation pushed by Husted that he said would stop data centres from raising electricity costs for residents and make the centres pay their own way. He said nearly every Senate Democrat had voted to block the measure days earlier.

The crowd was reportedly muted during his data centre remarks, showing how contentious the projects have become. Voters in Ohio and other states have raised concerns about electricity bills, water use and farmland.

Trump told supporters to vote as though he himself were on the ballot in the November 3 midterms. The Ohio stop is part of a planned 32-day campaign tour.