Melania Trump is reportedly trapped inside her hotel in Hamburg due to anti-capitalist protesters surrounding the building.

The First Lady was due to be involved in an event for the spouses of leaders taking part in the G20 summit, organised by Angela Merkel’s husband.

But a spokesperson for the US delegation told German media that they had been unable to get clearance for Ms Trump to leave the hotel where she is staying.

Ms Trump has expressed her sympathies for those hurt in the protests which erupted across Germany's second largest city and urged people to remain safe on Twitter.

President Trump made it to the summit on time after driving through the city at a fast speed under heavy police escort.

The German Chancellor’s husband, Joachim Sauer, was due to take Ms Trump on a tour of the German Climate Computing Centre with the US President's daughter, Ivanka Trump, and other spouses of G20 leaders on Friday.

German officials said the idea for the visit came from Mr Sauer who is a professor of physical and theoretical chemistry.

The centre, which uses super-computers to map climate change’s effect on regions across the world, is situated near the secured hall where Ms Merkel, President Trump, and other leaders are meeting.

Other partners, including Ms May's husband Philip, Emmanuel Macron's wife Brigitte Macron, and Canadian Prime Minister Justin Trudeau's wife Sophie Gregoire Trudeau are currently on the sightseeing tour with Mr Sauer which also involves a boat ride and lunch.

Malcolm Turnbull, the Australian prime minister, tweeted that he was under “security lockdown” with the Indonesian president, Joko Widodo. Police protecting the hotel where Mr Turnbull is staying briefly came face to face with protestors at one point.

At least 76 people were hurt in clashes with police in Hamburg as the force used water cannons on black-clad protesters who threw water bottles.

The "Welcome to Hell" rally is one of a number of protests held in the city against both the G20 summit and Mr Trump's maiden appearance there.

Iran's 'Trumpism' contest Show all 10 1 /10 Iran's 'Trumpism' contest Iran's 'Trumpism' contest A picture taken on July 3, 2017 shows a cartoon of US President Donald J. Trump and First Lady Melania Trump on display at an exhibition of the Islamic Republic's 2017 International Trumpism cartoon and caricature contest, in the capital Tehran. / AFP PHOTO / ATTA KENARE (Photo credit should read ATTA KENARE/AFP/Getty Images) AFP/Getty Images Iran's 'Trumpism' contest An Iranian woman looks at cartoons of US President Donald J. Trump at an exhibition of the Islamic Republic's 2017 International Trumpism cartoon and caricature contest, in the capital Tehran on July 3, 2017. / AFP PHOTO / ATTA KENARE (Photo credit should read ATTA KENARE/AFP/Getty Images) AFP/Getty Images Iran's 'Trumpism' contest An Iranian woman looks at cartoons of US President Donald J. Trump at an exhibition of the Islamic Republic's 2017 International Trumpism cartoon and caricature contest, in the capital Tehran on July 3, 2017. / AFP PHOTO / ATTA KENARE (Photo credit should read ATTA KENARE/AFP/Getty Images) AFP/Getty Images Iran's 'Trumpism' contest Iranian cartoonist Hadi Asadi poses for a picture with a trophy and an award next to cartoons of US President Donald J. Trump, at an exhibition of the Islamic Republic's 2017 International Trumpism cartoon and caricature contest, in the capital Tehran on July 3, 2017. / AFP PHOTO / ATTA KENARE (Photo credit should read ATTA KENARE/AFP/Getty Images) AFP/Getty Images Iran's 'Trumpism' contest Iranians look at cartoons of US President Donald J. Trump at an exhibition of the Islamic Republic's 2017 International Trumpism cartoon and caricature contest, in the capital Tehran on July 3, 2017. / AFP PHOTO / ATTA KENARE (Photo credit should read ATTA KENARE/AFP/Getty Images) AFP/Getty Images Iran's 'Trumpism' contest An Iranian woman looks at cartoons of US President Donald J. Trump at an exhibition of the Islamic Republic's 2017 International Trumpism cartoon and caricature contest, in the capital Tehran on July 3, 2017. / AFP PHOTO / ATTA KENARE (Photo credit should read ATTA KENARE/AFP/Getty Images) AFP/Getty Images Iran's 'Trumpism' contest Iranian reformist cleric Mahmoud Doaei looks at cartoons of US President Donald J. Trump at an exhibition of the Islamic Republic's 2017 International Trumpism cartoon and caricature contest, in the capital Tehran on July 3, 2017. / AFP PHOTO / ATTA KENARE (Photo credit should read ATTA KENARE/AFP/Getty Images) AFP/Getty Images Iran's 'Trumpism' contest An Iranian man looks at cartoons of US President Donald J. Trump at an exhibition of the Islamic Republic's 2017 International Trumpism cartoon and caricature contest, in the capital Tehran on July 3, 2017. / AFP PHOTO / ATTA KENARE (Photo credit should read ATTA KENARE/AFP/Getty Images) AFP/Getty Images Iran's 'Trumpism' contest An Iranian woman looks at cartoons of US President Donald J. Trump at an exhibition of the Islamic Republic's 2017 International Trumpism cartoon and caricature contest, in the capital Tehran on July 3, 2017. / AFP PHOTO / ATTA KENARE (Photo credit should read ATTA KENARE/AFP/Getty Images) AFP/Getty Images Iran's 'Trumpism' contest Iranian reformist cleric Mahmoud Doaei looks at cartoons of US President Donald J. Trump at an exhibition of the Islamic Republic's 2017 International Trumpism cartoon and caricature contest, in the capital Tehran on July 3, 2017. / AFP PHOTO / ATTA KENARE (Photo credit should read ATTA KENARE/AFP/Getty Images) AFP/Getty Images

Police said beforehand they were expecting up to 100,000 demonstrators to descend on the city and around 20,000 police would be safeguarding the summit.

Ahead of the protests, reports emerged suggesting demonstrators were planning to take advantage of the decision to hold the summit in a busy inner-city area and emulate police crowd control strategies to “kettle Trump, Putin and Erdogan”.

Hamburg, the birthplace of Chancellor Merkel, is a hub for counter cultural movements and home to many radical left-wing and anarchist groups.