WASHINGTON--Donald Trump met with one of America’s biggest unions on Wednesday as he competes for the support of labor groups ahead of a likely general election rematch with Democratic President Joe Biden in November.

Trump sat down with the leadership and some rank-and-file members of the 1.3-million member International Brotherhood of Teamsters, just days after the Republican former president reacted angrily to losing out on the endorsement from another major union, the United Auto Workers.

Trump said if elected he would block Japan’s Nippon Steel planned $14.9 billion acquisition of U.S. Steel. “I would block it instantaneously. Absolutely,” he said in response to a question from Reuters.

Trump’s meeting with the Teamsters that represent truck drivers, dockworkers, airline pilots, government employees and many other sectors came during a 2024 presidential campaign in which the economy is front and center, and unions have seen a resurgence in the United States with many, including the Teamsters, winning new significant contracts.

Trump and Biden will likely target union votes in general election battleground states, including Michigan and Pennsylvania. Trump’s grip on the Republican presidential nomination has tightened after back-to-back nominating wins in Iowa and New Hampshire this month.

After the meeting, Trump was skeptical about whether Teamsters leadership would endorse him - they endorsed Biden before the 2020 election - but he claimed to have strong support among the union’s rank-and-file members.

Trump said his pledge to impose tariffs on Chinese goods, and to reduce the flow of illegal immigrants across the U.S.-Mexico border, is supported by many union members.

“I’ve dealt with unions my whole life, I have a great relationship with unions,” Trump said. “We had a very good discussion.”

Teamsters President Sean O’Brien said the union had a pleasant, direct and engaging meeting with Trump and said it might be several months before it makes an endorsement.

O’Brien said Biden “has done a lot of good work for union members” but added “what you’ve done in the past doesn’t guarantee future events. We want to know what you’re going to do for our members moving forward.”

The union is mulling which presidential candidate it will endorse ahead of November’s election.

Two hours before the scheduled meeting, the Trump campaign released a list of pledges by Trump, claiming that U.S. workers will benefit from his policies. They include tariffs on Chinese imports - a move many economists say will hurt U.S. workers and consumers - and closing the U.S.-Mexico border, another pledge that economists warn will adversely affect American manufacturers.

The Biden campaign said “the President looks forward to meeting with the Teamsters and earning their endorsement.”

Union endorsements could be crucial in a presidential race among a closely divided electorate where just a few thousand votes in several key states could decide the 2024 election.

Since he first ran for president in 2016, Trump has increased support among blue-collar workers and is again telling them this year that he - and not Biden - will improve their lives economically.

Biden calls himself the most pro-union president in history and has taken many pro-labor actions, and the Teamsters endorsed him in 2020.

Biden received a coveted endorsement last week, from the leadership of the almost 380,000-strong United Auto Workers (UAW), another key labor group in the Midwest, an important election battleground.

Separately, Biden will be in Michigan on Thursday for a visit to a Detroit-area union hall to meet with UAW members.

UAW President Shawn Fain said that Biden had a history of serving the working class, while Trump “stands against everything we stand for,” citing among other things Trump’s appearance at a non-union hall during last year’s auto workers strike. He called Trump an anti-union “scab.”

Trump reacted furiously on his Truth Social platform on Sunday, calling Fain a “stiff” and a “dope,” and urging auto workers to vote for him and not Biden in November.