Chinese ride-sharing firm Didi Chuxing said Thursday it had raised $4 billion from investors, months after a funding round that made it Asia’s most valuable startup, as it presses on with a global battle with US giant Uber.

Local and foreign groups contributed to the huge pot, which will be used to fuel Didi's global expansion and support new developments in artificial intelligence and new energy vehicles, the company said in a statement.

Didi, which bought Uber's China operations last year, has nearly half a billion users around the world and handles up to 25 million rides per day. It will see its valuation rise to $56 billion, sources close to the matter told AFP.

It became Asia’s most valuable startup in April with a valuation of $50 billion after its previous round of fundraising.

Uber and Didi have been fighting a global turf war since Didi bought out the US firm's China operations.

Didi has been battling for international market share with Uber by working with local firms through investment or partnership, including Southeast Asia’s Grab, India’s Ola, US-based Lyft, and Europe’s Taxify.

Bloomberg News reported in October that Didi was also in talks with Japanese taxi operator Daiichi Koutsu Sangyo to provide riding services for Chinese tourists in Japan.

Japanese telecoms giant Softbank, which already has stakes in the Chinese firm, is among the backers in the latest fundraising round along with Abu Dhabi’s Mubadala Capital, the sources said.

More than 260,000 electric vehicles are running on Didi’s network now and the firm has also set up a joint venture to build its own charging networks, the firm’s chief executive Cheng Wei said last month.