LONDON (Kyodo) -- Senior U.S. and Chinese officials met in London on Monday, with a top economic adviser to President Donald Trump expecting the latest round of trade talks to result in Beijing promptly lifting its export controls on rare earth minerals.

The second high-level meeting, following mid-May talks in Geneva, took place after Trump and Chinese President Xi Jinping spoke by phone last week, their first known direct communication since the U.S. president's inauguration for a nonconsecutive second term in January.

U.S. Treasury Secretary Scott Bessent, Commerce Secretary Howard Lutnick and Trade Representative Jamieson Greer attended the talks, which could also continue Tuesday. The trio met with a Chinese delegation led by Vice Premier He Lifeng, a longtime confidant of Xi who oversees economic affairs.

On Monday, Kevin Hassett, director of the National Economic Council, struck an optimistic note about the meeting's anticipated outcome.

Hassett said in an interview with CNBC that the talks are likely to end with a "big, strong handshake."

"Our expectation is that after the handshake, then immediately...any export controls from the U.S. will be eased, and the rare earths will be released in volume, and then we can go back to negotiating smaller matters," he said.

The 90-minute phone conversation between Trump and Xi on Thursday came after Washington and Beijing exchanged barbs over alleged violations of a preliminary agreement reached in Geneva.

Under the deal, the two countries established a 90-day truce in their trade war and committed to stepping back from their respective triple-digit tariff rates.

In the days leading up to his call with Xi, the Trump administration expressed frustration over China's slow removal of export controls on critical minerals used in high-tech products, accusing Beijing of failing to uphold the terms of the initial deal.

China had criticized the Trump administration for imposing "discriminatory measures," including export control guidance on artificial intelligence chips and the revocation of visas for Chinese students studying in the United States.

China's Commerce Ministry said Saturday that Beijing has approved a number of export license applications for rare earth-related items, citing global demand from industries such as robotics and new energy vehicles. However, it did not provide further details.

China mines about 70 percent of the world's rare earths that are used in the production of smartphones, personal computers and vehicles. As part of retaliatory measures against high U.S. tariffs, Beijing in April introduced export controls on seven types of rare-earth minerals.

Amid a tit-for-tat tariff war, Chinese exports to the United States in May fell 34.5 percent from a year earlier to $28.8 billion, while Chinese imports from the country dropped 18.1 percent to $10.8 billion, customs data of the Asian powerhouse showed Monday.