Joe Biden calls for probe into US Steel sale to Japan's Nippon

The White House says Nippon Steel's plan to buy US Steel should be probed on national security grounds,even though Japan is a "close ally".

It also expressed concern about the deal's potential impact on supply chain reliability in a Thursday statement.

The $15bn (£12bn) purchase of the 122-year-old steelmaker would create one of the world's biggest steel companies.

But the powerful United Steelworkers (USW) union also criticised the deal as "shortsighted".