Dozens of supporters of President Donald Trump chanting “Stop the count!” descended on a ballot-tallying center in Detroit on Wednesday, while thousands of anti-Trump protesters demanding a complete vote count in the still-undecided presidential contest took to the streets in cities across the U.S.

In New York City, thousands marched past boarded-up luxury stores on Manhattan’s Fifth Avenue, calling for every vote to be tallied. The march was largely peaceful, though police said they made at least 20 arrests after a smaller, rowdier group began protesting police misconduct by blocking traffic and setting fires.

In Chicago, protesters demanding a complete count marched through downtown and along a street across the river from Trump Tower.

Similar protests — sometimes about the election, sometimes about racial inequality — took place in at least a half-dozen cities, including Los Angeles, Seattle, Houston, Pittsburgh, Minneapolis and San Diego.

In Portland, Oregon, which has been a scene of regular protests for months, Gov. Kate Brown activated the National Guard after demonstrators engaged in what authorities said was widespread violence downtown, including smashing windows. Protesters in Portland were demonstrating about a range of issues, including police brutality and the counting of the vote.

Richard March came to an anti-Trump demonstration in Portland despite a heart condition that makes him vulnerable to COVID-19.

“To cast doubt on this election has terrible consequences for our democracy,” he said. “I think we are a very polarized society now — and I’m worried about what’s going to come in the next days and weeks and months.”

The confrontation in Detroit started shortly before The Associated Press declared that former Vice President Joe Biden had won Michigan.

Video shot by local media showed angry people gathered outside the TCF Center and inside the lobby, with police officers lined up to keep them from entering the vote-counting area. They chanted, "Stop the count!” and “Stop the vote!”

Earlier, the Republican campaign filed suit in a bid to halt the count, demanding Michigan's Democratic secretary of state allow in more inspectors. Trump has repeatedly insisted without evidence that there are major problems with the voting and the counting.

Michigan Attorney General Dana Nessel, a Democrat, insisted both parties and the public had been given access to the tallying “using a robust system of checks and balances to ensure that all ballots are counted fairly and accurately.”

Michigan has been on edge for months over fears of political violence. Anti-government protesters openly carried guns into the state Capitol during protests over coronavirus restrictions in the spring, and six men were arrested last month on charges of plotting to kidnap Democratic Gov. Gretchen Whitmer

On Election NIght, scattered protests broke after voting ended, stretching from Washington, D.C., to Seattle, but there was no widespread unrest or significant violence.

The prolonged task of counting this year's deluge of mail-in votes raised fears that the lack of clarity in the presidential race could spark unrest. (AP)