The songstress Madonna made a surprise appearance in the massive Women's March in Washington that included many artistes that refused to attend Donald Trump's inauguration as President of the United States this Friday.

EFE news quoted Madonna as saying that she had "thought an awful lot about blowing up the White House" after Trump won the November 8 election, but instead she chose a "revolution of love".

She immediately proclaimed that "the revolution starts here," and added "To the rebellion. To our refusal as women to accept this new age of tyranny."

"Yes, I'm angry. Yes, I am outraged," she said, and for those who criticised the protests, she offered a "big old F××× You."

With the same strength, she danced and sang her 1989 hit "Express Yourself" at a place near the Capitol, where demonstrators had been gathering since the early hours.

The huge sea of protesters from cities all over the country exceeded the expectations of organisers, who put the number of participants at at least a half million, double what had been expected, EFE news reported.

Authorities in the US capital likewise said around 500,000 people were taking part in the march.

One indicator of the size of the crowd was the number of Washington Metro passengers, which numbered 275,000 people as of 11.00 am on Saturday, up from the 193,000 who had ridden that transit system as of that same time on Inauguration Day.

Among those participating in the march was former Secretary of State John Kerry, who spoke with other demonstrators while walking his dog.

The day's events began with a mass rally near the US Capitol building, with huge numbers of people packing nearby streets and parks.

For three hours, speakers including actresses Scarlett Johansson, Ashley Judd and America Ferrera, as well as prominent liberal documentary filmmaker Michael Moore, called for the protection of civil and human rights and slammed Trump.

Moore ripped up a Saturday newspaper with news of Trump's inauguration on the front page.

The entire city was a sea of pink pussycat hats, which large numbers of female demonstrators were wearing to mock Trump for comments caught on a 2005 video clip, in which the then reality TV star boasted about leveraging his celebrity status to grope women with impunity, EFE news added.

Some of the signs demanded respect for women's rights, while others accused Trump of playing on voters' fears during the campaign.

Hundreds of sister marches also took place across the US, while anti-Trump demonstrations also were held in cities around the world.