American President-elect Joe Biden will nominate retired four-star Army general, Lloyd J. Austin to be Secretary of Defense, US media report.

If confirmed by the Senate, Austin would be the first Black leader of the Pentagon.

Mr Biden has been facing calls including from Democratic Asian, Black and Latino caucuses to nominate minorities to senior cabinet posts.

Biden selected Austin over the longtime front-runner candidate, Michele Flournoy, a former senior Pentagon official and Biden supporter who would have been the first woman to serve as defense secretary.

Four-star Gen. Austin served under the Obama administration, leading the US Central Command, whose area of responsibility includes the Middle East, Central Asia and part of South Asia, between 2013 and 2016. He was the main military architect of the US-led offensive against the Islamic State group in Iraq and Syria.

Before that he was Vice-Chief of Staff of the Army and the last Commanding General of the US forces in Iraq. During these years he worked closely with Mr Biden, who was Vice-President in the Barack Obama administration.