NEW YORK - US Senator Bernie Sanders and former Secretary of State Hillary Clinton had one of their sharpest exchanges of the Democratic presidential campaign to date during Sunday's debate in Flint, Michigan, disagreeing over trade, guns and the auto industry bailout while joining forces to call for the resignation of state governor Rick Snyder over the city’s water contamination crisis.

Shortly after they took the stage, the Associated Press, the American wire service, announced that Sanders had won the Democratic caucuses in Maine, his eighth victory in the 2016 presidential primary race. In a statement, the leftwing Vermont senator thanked Maine’s voters and claimed “momentum” heading into Tuesday’s primaries in Michigan and Mississippi.

Sanders accused Mrs. Clinton of being in the pocket of Wall Street and charged that she, along with her husband, made decisions two decades ago that have devastated the middle class, while the former secretary of state shot back and said her presidential primary rival would have let the American auto industry go bankrupt.

The senator came out swinging against Mrs. Clinton and said massive free trade deals she supported, such as NAFTA, have contributed to slowing the American economy.NAFTA was enacted in the 1990s when President Bill Clinton was in office.

Sanders also blasted Mrs. Clinton for supporting normalized trade relations with China and other agreements.

“Your story is voting for every disastrous trade agreement and voting for corporate America,” Sanders said, again tying Mrs. Clinton to Wall Street and zeroing in on her paid speeches to Goldman Sachs.

He also mocked Mrs. Clinton, saying she only recently “found religion” on the issue of corporate America and Wall Street firms moving jobs overseas to make more money.“One of us has a super PAC (Political Action Committee). One of us has raised $15 million from Wall Street for that super PAC. One of us has given speeches on Wall Street for hundreds of thousands of dollars,” he said. “Now, I kind of think if you get paid a couple of hundred thousand dollars for a speech, it must be a great speech. I think we should release it and let the American people see what that transcript was

Mrs. Clinton again refused to release her Goldman Sachs transcripts unless all other presidential candidates, including Republicans, release full transcripts of their paid speeches as well.

But Mrs. Clinton also returned fire on Sanders and criticized him for voting against a $350 billion package in 2009 that included a bailout for General Motors and Chrysler. Sanders has said he voted against the legislation because it bailed out Wall Street billionaires.

“He was against the auto bailout,” Mrs. Clinton said. “The money was there and had to be released in order to save the auto industry and 4 million jobs. … I voted to save the auto industry; he voted against the money that ended up saving the auto industry.”

She also attacked Sanders for voting against the Export-Import bank, a federal agency that offers loans to American companies exporting products.

Sanders has voted against the bank and considers it a form of corporate welfare, but Mrs. Clinton argues that it is necessary to keep U.S. firms competitive in a global marketplace. “I think we’re in a race for exports,” she said.

The debate took place against the backdrop of the Flint water crisis, and both candidates said Governor Snyder should step down immediately. Both candidates also made clear that they believe Environmental Protection Agency officials should resign if they are found to have been negligent, and both also left open the possibility of criminal charges against public officials.

“People should be held accountable, wherever that leads,” Mrs. Clinton said. “If it leads to resignations or recall if you’re in political office, it if leads to civil penalties, if it leads to criminal responsibility, there has to be an absolute accountability and I will support whatever the outcomes of those investigations are.”