By K. Sophie Will

LONDON, Nov 21 (Thomson Reuters Foundation) - Extinction Rebellion activists pressing for more rapid action on climate change threats on Wednesday entered a third day of a week-long hunger strikes in 27 countries.

The strikes, which began Monday, have been in part spearheaded by 20-year-old Giovanni Tamacas, a University of San Diego student, who carried out a solo hunger strike last month in front of the White House.

"We are hunger striking because we have no choice," he said in a statement, arguing governments and corporations "have criminally and catastrophically failed to tackle the climate and ecological emergency."

In the United States, activists started their strike by occupying the office of US House of Representatives Speaker Nancy Pelosi, who protesters said has refused to participate in a filmed interview with movement members.

Pelosi did issue a statement saying she was "inspired" by young climate activists and that US Democrats were "working relentlessly to safeguard our environment and ensure a healthy, sustainable world for our children."

Today, hundreds of thousands of young people all over the world will skip school to protest climate change. Here's why they're doing it. pic.twitter.com/OzYjjFjWQF

— Global Citizen UK (@GlblCtznUK) May 24, 2019

In Britain, a handful of activists protested at headquarters of the Conservative, Labour, and Liberal Democrat parties, similarly demanding that candidates in upcoming British elections submit to filmed interviews with Extinction Rebellion members.

Activists around the world signed up to carry out hunger strikes in countries ranging from the Democratic Republic of Congo to New Zealand, Pakistan and Turkey, Extinction Rebellion organisers said.

Extinction Rebellion campaigners said the strikes were being carried out in solidarity with people facing worsening hunger as a result of climate change and was aimed at highlighting "the lack of compassion" of many in power.

"You would rather watch communities be destroyed by the catastrophic hurricanes and floods the climate crisis will bring" than act on the threats, charged 17-year-old activist Sophia Kianni, from Virginia, in a statement.

The Extinction Rebellion movement uses peaceful civil disobedience to highlight the risks posed by climate change and accelerating species losses in the natural world.

It has called for governments to set a 2025 deadline to reduce climate-changing emissions to net zero, to declare climate emergencies and to set up citizen assemblies to give people a great voice in political decision making.

More than 1,800 Extinction Rebellion activists were arrested during two weeks of disruptive street protests in October in London, police said.

(Reporting by K. Sophie Will; editing by Laurie Goering. Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, climate change, resilience, women's rights, trafficking and property rights. Visit http://news.trust.org/climate)