Senate Minority Leader Chuck Schumer (D-NY) acknowledges reporters as he arrives for a closed Senate Democratic policy lunch on Capitol Hill in Washington, March 26, 2019.

As President Donald Trump reignites a trade war with China, he has found an ally in at least one key Democrat – Senate Minority Leader Chuck Schumer.

The New York senator, who has largely cheered the president's efforts to crack down on what officials from both major parties call Chinese trade abuses, backed Trump again on Sunday. In a tweet, he urged the president to "hang tough on China."

"Strength is the only way to win with China," said Schumer, who is otherwise at odds with Trump on a wide variety of policy issues.

Schumer tweet: Hang tough on China, President @realDonaldTrump. Don't back down. Strength is the only way to win with China.

The president plans to increase tariffs on $200 billion in Chinese goods to 25% from 10% on Friday, he tweeted Sunday. He also threatened to "shortly" put tariffs on the remaining $325 billion in Chinese products on which the U.S. has not put duties.

Trump's tariff threat upended trade talks with Beijing just as the White House touted progress toward a final agreement to resolve U.S. grievances such as intellectual property theft and trade deficits. U.S. and Asian stock markets plunged on Monday ahead of planned trade talks this week between Washington and Beijing.

While Schumer backed Trump's move, other top Democrats stayed quiet about Trump's trade war escalation as of Monday morning. Spokespeople for House Speaker Nancy Pelosi and Rep. Earl Blumenauer, an Oregon Democrat and head of the House Ways and Means Committee's trade subcommittee, did not immediately respond to requests to comment.