China is reportedly suing US President Barack Obama for blocking a Chinese-owned firm from buying four wind farm projects in the States.

The Chinese-owned Ralls Corp wanted to buy a handful of Oregon wind farm projects. Its lawsuit alleges the US government overstepped its authority.

Last Friday Obama signed a decree banning the sale, which could be seen as a move to appear tougher on Chinese trade to out-manoeuvre Republican rival Mitt Romney in the run up to November elections.

The Republican candidate has criticised the President for not protecting American interests.