Washington turned into a virtual fortress on Thursday ahead of Donald Trump's presidential inauguration, while thousands of people took to the streets of New York to express their displeasure with his coming administration.

Some 900,000 people, both Trump backers and opponents, are expected to flood Washington for Friday's inauguration ceremony, according to organizers' estimates. Events include the swearing-in ceremony on the steps of the US Capitol and a parade to the White House along streets thronged with spectators.

The number of planned protests and rallies this year is far above what has been typical at recent presidential inaugurations, with some 30 permits granted in Washington for anti-Trump rallies and sympathy protests planned in cities from Boston to Los Angeles, and abroad in cities including London and Sydney.

The night before the inauguration, thousands of people turned out in New York for a rally at the Trump International Hotel and Tower, and then marched a few blocks from the Trump Tower where the businessman lives.

The rally featured a lineup of politicians, activists and celebrities including Mayor Bill de Blasio and actor Alec Baldwin, who trotted out the Trump parody he performs on Saturday Night Live.

"Donald Trump may control Washington, but we control our destiny as Americans," de Blasio said. "We don't fear the future. We think the future is bright, if the people's voices are heard."

In Washington, police cars lined much of Pennsylvania Avenue, the parade route, as workers unloaded crowd control fences from flatbed trucks, erected barricades and marked off pavement with tape.

US Department of Homeland Security Secretary Jeh Johnson said police aimed to keep groups separate, using tactics similar to those employed during last year's political conventions.

"The concern is some of these groups are pro-Trump, some of them are con-Trump, and they may not play well together in the same space," Johnson said on MSNBC.

Trump opponents have been angered by his comments during the campaign about women, illegal immigrants and Muslims and his pledges to scrap Obamacare health reform and build a wall on the Mexican border.

The Republican's supporters admire his experience in business, including as a real estate developer and reality television star, and view him as an outsider who will take a fresh approach to politics.

Bikers for Trump, a group that designated itself as security backup during last summer's Republican National Convention in Cleveland, is ready to step in if protesters block access to the inauguration, said Dennis Egbert, one of the group's organizers.

"We're going to be backing up law enforcement. We're on the same page," Egbert, 63, a retired electrician from Harrisburg, Pennsylvania.

About 28,000 security personnel, miles of fencing, roadblocks, street barricades and dump trucks are part of the cordon around three square miles of central Washington.