It is the highest profile Chinese deal to be rejected by Washington since Donald Trump came to power.

Regulators overseeing foreign investments in the US had refused to support the takeover, the firms said.

The geopolitical environment had "changed considerably" since the merger was announced last year, they added.

'Disappointed'

The collapse is a blow to the ambitions of Alibaba's billionaire executive chairman Jack Ma, who had promised President Trump that he would create a million US jobs.

Alibaba, which owns Ant Financial together with Alibaba executives, saw the US market as a way to expand overseas in the face of fierce domestic competition from the likes of Tencent's WeChat.

But in a joint statement on Tuesday, Ant Financial and Moneygram said they had abandoned the deal after failing to "obtain the required approval for the transaction from the Committee on Foreign Investment in the United States, despite extensive efforts to address the Committee's concerns".

Reports suggest the committee had cited security concerns over the takeover.

Moneygram chief executive Alex Holmes said he was disappointed by the outcome and noted the "geopolitical environment has changed considerably" in the year since the deal was announced.

Deals blocked

The US has been toughening its stance on business dealings with China.

The country launched a formal review of China's intellectual property practices in October last year. US politicians and military leaders have also urged the administration to take a closer look at Chinese investments in America, particularly in the technology industry.

In September, the US blocked the $1.3bn sale of US Lattice Semiconductor to Chinese-backed Canyon Bridge Capital Partners, citing concerns over the "potential transfer" of intellectual property from Lattice, which makes advanced computer chips.

Other deals that have been frustrated by US objections include China Oceanwide Holdings Group's $2.7bn purchase of US life insurer Genworth Financial, and Chinese buyout firm Orient Hontai Capital's $1.4bn acquisition of US mobile marketing firm AppLovin.