Donald Trump’s inauguration as president prompted a series of protests in cities around the world on Saturday, called in defense of the equality and diversity seen by organizers as under threat in the era of the new U.S. administration.

The Wall Street Journal reports hundreds of thousands of people flooded U.S. cities to protest for women’s rights and mark President Donald Trump’s first full day in office. 

Reuters says thousands of women took to the streets of European capitals to join “sister marches” in Asia against newly installed U.S. President Trump ahead of a major rally in Washington.

Waving banners with slogans like "Special relationship, just say no" and "Nasty women unite," the demonstrators reportedly gathered outside the American embassy in Grosvenor Square before heading to a rally in central Trafalgar Square.

Celebrities including rights activist Bianca Jagger, singer Charlotte Church and actor Ian McKellen expressed their support for the protest on social media.

In Europe, marches also took place in Berlin, Paris, Rome, Vienna, Geneva and Amsterdam.

In Africa, hundreds of protesters in Nairobi's Karura Forest waved placards and sang American protest songs.

In Sydney, Australia's biggest city, about 3,000 people - men and women - gathered for a rally in Hyde Park before marching on the U.S. consulate downtown, while organizers said 5,000 people rallied in Melbourne.

In New Zealand, there were marches in four cities, involving around 2,000 people, Wellington's march organizer Bette Flagler told Reuters.