US lawmakers waited on Sunday for details of a confidential report into an investigation of Russian meddling in the 2016 election that has cast a pall over Donald Trump’s presidency and raised questions about possible collusion between the Republican’s campaign and Moscow.

Republican presidential nominee Mitt Romney was desperately trying to steady a shaky campaign as US President Barack Obama, enjoying a burst of momentum, headed to New York for a celebrity fundraiser with Beyoncé and Jay-Z, along with a star turn on David Letterman’s couch.