Donald Trump has said he “very easily” answered written questions from special counsel Robert Mueller, although he speculated that the questions had been “tricked up” to try to catch him in a lie.

The president said he had not yet submitted his answers to investigators.

“You have to always be careful when you answer questions with people that probably have bad intentions,” he told reporters in his latest swipe at the probe into 2016 election interference and possible ties between Moscow and the president’s campaign.

He did not say when he would turn over the answers to Mr Mueller, but his lawyer Rudy Giuliani indicated it could happen next week.

The special counsel has signalled a willingness to accept written answers on matters related to collusion with Russia, but Mr Giuliani has said repeatedly the president would not answer Mr Mueller’s questions on possible obstruction of justice.

During months of negotiations with the special counsel office, Mr Trump’s lawyers have repeatedly counselled the president against sitting down for an in-person interview.

His written response, though not yet delivered, signals a new phase in the Mueller probe, the year-and-a-half-long investigation that has produced guilty pleas and convictions from several top Trump aides even as the special counsel and the White House have engaged in lengthy negotiations about how — or if — the president would give evidence.

Though he spent hours with his lawyers, Mr Trump insisted: “My lawyers don’t write answers, I write answers.”

The president’s remarks were fresh evidence of his return to the ominous rhythms of the Russia probe after spending heady weeks enjoying adulation-soaked campaign rallies before the midterm elections.

Despite his insistence that he is “very happy” with how things are going, his frustrations with the ongoing probe have been evident everywhere from his overheated Twitter feed this week to his private grousing that the special counsel may target his family.

Adding to his grim outlook has been a barrage of criticism over his choice for acting attorney general and late-arriving election results that have largely been tipping towards House Democrats.

“The inner workings of the Mueller investigation are a total mess,” Mr Trump tweeted on Thursday as part of a series of morning posts. The investigators don’t care “how many lives they can ruin”, he wrote.

A day later, he tried to put a rosier shine on the situation, telling reporters: “I’m sure it will be just fine.”