President Donald Trump's top trade envoy said Sunday that the U.S. president exacted a commitment from the Chinese to not "provide material support to Iran," but that the United States did not seek China's direct help to reopen the Strait of Hormuz.

"When the president went in, he did not go in asking them to take action in the Straits of Hormuz. He was very focused on making sure that they didn't provide material support to Iran. That's a commitment he obtained and confirmed," U.S. Trade Representative Jamieson Greer said on ABC News' "This Week."

Greer said China has "a clear interest" in reopening the strait -- "I was in these meetings, and that's what, that's what the Chinese said," he said -- but without getting involved directly, it's unclear whether China's position will do anything to pressure Iran.

"The president isn't seeking to have joint military operations with the Chinese. I don't think the American presidents have ever done that," Greer said. "But obviously we want to make sure that they're not getting in the way of anything we're doing to try to clarify that situation."

-ABC News' Quinn Scanlan

A drone attack caused a fire in an electrical generator at a nuclear power plant in the United Arab Emirates, officials in Abu Dhabi said on Sunday.

The generator was "outside the inner perimeter" of the Barakah Nuclear Power Plant in the Al Dhafra Region, the Abu Dhabi Media Office said on social media.

"The Federal Authority for Nuclear Regulation (FANR) confirmed that the fire did not affect the safety of the power plant or the readiness of its essential systems, and that all units are operating as normal," officials said.

-ABC News' Mike Trew