UPDATE 1-Trump says "China is letting us down" on buying from U.S. farmers

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WASHINGTON, July 11 (Reuters) - U.S. President Donald Trump said on Thursday that China was not living up to promises it made on buying agricultural products from American farmers as the world's two largest economies work to resolve a trade dispute.

"Mexico is doing great at the Border, but China is letting us down in that they have not been buying the agricultural products from our great Farmers that they said they would. Hopefully they will start soon!" Trump said on Twitter.

White House economic adviser Larry Kudlow said on Thursday the United States expects China to start purchasing crops and U.S. agricultural products soon and noted that trade talks between the two countries are ongoing.

The United States and China agreed last month to restart trade talks that stalled in May. Trump agreed not to impose new tariffs and U.S. officials said China agreed to make agricultural purchases, but those have not yet materialized. (Reporting by Doina Chiacu; Editing by Chizu Nomiyama and Susan Thomas)