Hundreds of thousands of people have rallied across the globe in an international day of action on climate change, with the purported largest mobilisation of its kind in New York City.

More than 500,000 people took part in 2,500 marches  around the world on Sunday ahead of Tuesday's UN climate summit set to take place in New York, organisers said.

The pressure group Avaaz, which helped organise the rallies, said it was seeking to galvanise political will for a new global climate treaty by the end of 2015.

Organisers of the  New York rally  claimed it was the largest single protest ever over climate change, with an estimated 310,000 people attending. They included the UN secretary-general Ban Ki-moon and the former US presidential candidate Al Gore.

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More than 30,000 people gathererd in Melbourne, at least 15,000 rallied in a rain-soaked Berlin and an estimated 5,000 rallied in the Colombian capital Bogota.

In London, an estimated 40,000 people paraded past Trafalgar Square and the Houses of Parliament

Hundreds gathered in Sydney and in New Delhi, where about 300 protesters carried placards that read "I want to save forests" and "Coal kills", as they shouted slogans urging politicians to take action .

Ricken Patel, the executive director of Avaaz, presented a petition signed by two million people to Ban in New York.

"The march numbers are beating our wildest expectations," Patel said.

"In 2,500 marches from Paris to Bogota, we've blown past expected numbers. Climate change is not a green issue anymore, it's an everybody issue," he added.

Source: Al Jazeera and agencies