The White House said on Wednesday it will no longer answer questions about the ongoing investigations into Donald Trump’s alleged links to Russia.

James Comey, fired by Trump as director of the FBI, is reportedly due to testify to a congressional committee as early as next week.

Asked about Comey’s evidence and whether the president had engaged in obstruction of justice, press secretary Sean Spicer replied: “We are focused on the president’s agenda and going forward all questions on these matters will be referred to outside counsel Marc Kasowitz.”

Kasowitz is Trump’s longtime lawyer and has represented him in property deals, divorce cases and fraud allegations at Trump University.

Comey plans to confirm to the Senate intelligence committee allegations that Trump pressured him to drop an investigation into former national security adviser Michael Flynn’s links to Russia, according to a CNN report.

The broadcaster also said Comey has discussed the parameters of his congressional testimony with special counsel Robert Mueller, who is now leading the criminal investigation.

The White House made the announcement about its new policy on Russia questions just before the House intelligence committee issued subpoenas related to its Russia investigation. The subpoenas were approved for Flynn and Trump’s lawyer Michael Cohen and their related businesses.

Many of Spicer’s daily press briefings have been dominated by the Russia saga, much to his evident frustration, even though Trump’s tweets have often reignited the issue. His statement on Wednesday suggested that he is attempting to move on and, now a criminal investigation is under way, he feels uncomfortable about commenting without legal advice.

White House communications director Michael Dubke announced his resignation this week and, amid reports of an imminent shake up, there has been much speculation about Spicer’s future as press secretary. His demeanour on Wednesday was morose, his answers terse, in an off-camera briefing that lasted just 12 minutes.

Spicer was asked if Trump’s late-night tweet with the apparent typo “covfefe”, which lingered online for hours, is a matter of concern.

“No,” he answered gruffly, adding the extraordinary claim: “I think the president and a small group of people know exactly what he meant.”

As the room erupted in shouts and sarcastic comments, Spicer smiled briefly but ploughed on to the next question.

At 12.06am on Wednesday, Trump wrote: “Despite the constant negative press covfefe”, triggering a torrent of jokes on Twitter. The post, since deleted, was followed by another tweet at 6.09am that joked: “Who can figure out the true meaning of “covfefe” ??? Enjoy!”

Democratic US senator Al Franken, in a CNN interview, joked: “A covfefe is a Yiddish term for ‘I got to go to bed now’.”