For years, officials in Washington have used export controls to slow China’s ability to develop cutting-edge technologies, especially ones with military applications like semiconductors and artificial intelligence.

Over the past decade, these export controls have driven a wedge between the world’s two largest economies.

When officials from the United States and China met this week in London to try to work out their differences over trade, export controls were again front and center.

“In eight years of negotiating with the Chinese, I have never had a meeting where they didn’t want to talk about export controls,” Jamieson Greer, the United States Trade Representative, said on Tuesday.

It is not clear what actions U.S. officials agreed to take in exchange for China easing its exports of rare earth metals — a key sticking point for Washington. But the pillars of U.S. export controls to slow the flow of advanced technology to China appear to remain intact.