Rex Tillerson, nominated by Donald Trump to be the next secretary of state, was the longtime director of a US-Russian oil firm based in the tax haven of the Bahamas, leaked documents show. The chief executive of ExxonMobil became a director of the oil company's Russian subsidiary, Exxon Neftegas, in 1998. A leaked 2001 document listing him comes from the corporate registry in the Bahamas and was one of 1.3m files given to the German newspaper Süddeutsche Zeitung by an anonymous source. Though there is nothing untoward about this directorship, it has not been reported before and is likely to raise fresh questions over Tillerson's relationship with Russia as he heads for a confirmation hearing in the Senate.