WASHINGTON - The Obama administration will tell the US Congress on Friday it plans to upgrade Taiwan's existing fleet of F-16 fighter jets, said sources involved in a deal likely to anger China while disappointing a Taiwan government that was seeking more advanced aircraft.US-Taiwan Business Council President Rupert Hammond-Chambers, whose group lobbied for the sale of more advanced F-16 planes, said announcement of the upgrade was "imminent." Congressional sources said consultations with senior lawmakers' staff were expected on Friday.US arms sales to Taipei are a major point of friction with China, which claims sovereignty over the self-ruled island and has never renounced the use of force to bring Taiwan under its control, especially if Taiwan formally seeks independence.