US media reports that special counsel Robert Mueller has warned he could issue a subpoena for Donald Trump to appear before a grand jury as part of a probe into alleged Russian election meddling. Mr Mueller suggested the move during talks with Mr Trump’s lawyers in march. He said the subpoena would compel the president to face investigators, the Washington post reports. According to the Washington post, during the meeting in march, trump’s lawyers insisted that the president was under no obligation to face questions by federal investigators in relation to the Russia inquiry, which cited four people familiar with the encounter.