US President Donald Trump has responded to a guilty plea by his former national security adviser Michael Flynn, saying Flynn’s actions as a member of his transition team “were lawful”.

Flynn has entered a plea deal and agreed to co-operate with an inquiry into alleged collusion with Russia.

The deal, for a lesser charge than he might have faced, prompted speculation that he has incriminating evidence.

The president wrote on twitter on Saturday that he had “nothing to hide”.

Mr Flynn is co-operating with special counsel Robert Mueller, who is leading an investigation into alleged ties between the trump campaign and Russia ahead of the 2016 election.

On Saturday, a day after Mr Flynn’s indictment, it emerged that a veteran FBI agent had been dismissed from Mr Mueller’s team after the discovery that he had sent anti-trump text messages.