Top trade negotiators from the U.S. and China are set to hold fresh talks in London on Monday, offering a glimmer of hope that the world’s two largest economies can defuse tensions over Chinese dominance in rare-earth minerals.

Both sides have accused the other of reneging on a deal in Geneva in May where they tried to start dialing back their trade war. Relations have spiraled since President Donald Trump’s return to the White House, stoking uncertainty for companies and investors.

China said Saturday it approved some applications for rare-earth exports, without specifying which countries or industries were involved — after Trump said Friday that Chinese President Xi Jinping had agreed to restart the flow of minerals and magnets using the materials.