Apple CEO Tim Cook says President Donald Trump made the wrong decision when he pulled the United States out of the Paris climate agreement last week.

After much speculation and lobbying from both sides, the president kept his campaign promise to withdraw, though he said he was open to negotiating a deal that is more fair. (After the press conference, France, Germany, and Italy issued a joint statement saying that the agreement can’t be negotiated, according to The Associated Press.)

Speaking to Bloomberg at the company’s annual WWDC conference in San Jose, California, yesterday, Cook said that Trump “decided wrong.”

“I think it’s not in the best interest of the United States what he decided,” he said. “But in terms of, ‘do you interact with politicians or do you not,’ my view is that first and foremost things are about, can you help your country and if you can help your country and you do that by interacting, then you do it. The country eclipses politics.”

Cook personally called Trump to try to convince the president not to withdraw from the climate agreements. He was far from the only tech industry leader who tried to sway Trump. Ahead of the decision, the execs of 25 major companies’ executives all signed a letter in favor of the agreement that was published as a full-page ad in The New York Times and The Wall Street Journal. Tesla CEO Elon Musk also had hoped that Trump would remain.

In the wake of the decision, Musk has now left the president’s advisory council due to the decision. Many Silicon Valley leaders — including the CEOs of Microsoft, Facebook, and Google — have all said they remain committed to the agreement, and three US states have created a coalition to fight climate change.