President Donald Trump said he has asked China to immediately remove all tariffs on U.S. agriculture, including beef and pork, citing progress in trade talks between the two nations.

In making the demand, Trump noted in a tweet Friday that he refrained from increasing U.S. tariffs on Chinese goods to 25 percent from 10 percent on March 1, as he said he would in the absence of progress toward an agreement. Faxes and phone calls to China's ministries of commerce and foreign affairs, and the office in charge of trade talks, went unanswered Saturday outside office hours.

China imposed retaliatory tariffs on American agricultural products last year. But Trump did not indicate that his demand was limited to those penalties.