President Donald Trump fired off a series of tweets on topics spanning the Russia investigation through border security on Thursday night.

The tweets came the night before the special counsel Robert Mueller was expected to submit several important filings related to the Russia investigation.

Trump sent more tweets Friday morning, repeating his refrain that the investigation was a "witch hunt" and accusing Mueller of having conflicts of interest.

Friday is the deadline for Mueller to submit documents outlining allegations that Trump's former campaign chairman Paul Manafort lied in violation of his plea deal with the special counsel.

Mueller's office is also expected to submit a sentencing recommendation for the former Trump attorney Michael Cohen, who has pleaded guilty to financial crimes and, more recently, lying to Congress.

President Donald Trump fired off a series of tweets on a range of topics on Thursday evening, the night before the special counsel Robert Mueller was expected to submit several important filings related to the Russia investigation.

Trump fired off two tweets relating to a Fox Business segment in which the anchor Trish Regan sought to cast doubt on the FBI's justification for obtaining a FISA warrant to surveil the former Trump campaign adviser Carter Page.

Regan suggested the FBI was "weaponized in order to take down President Donald Trump."

"Is this really America?" Trump tweeted. "Witch Hunt!"

In another tweet one minute later, Trump appeared to revive a particularly inflammatory attack on the news media, saying only "FAKE NEWS - THE ENEMY OF THE PEOPLE!"

Trump went on to mention Arizona, which he claimed was "bracing for a massive surge at a NON-WALLED area."

US President Donald Trump stands for a group photo prior to the Three Seas Initiative transatlantic roundtable. Evan Vucci/AP Photo

Trump appeared to be referring to the Customs and Border Patrol's training exercise in Tucson, Arizona, on Thursday, where agents prepared "to deal with the potential of large crowds and assaultive behavior by caravan members, should a situation arise."

Trump also mentioned the Democratic lawmakers Nancy Pelosi and Chuck Schumer, who refused to support Trump's plans for a $5 billion down payment to fund a wall on the US-Mexico border.

"WE WILL NOT LET THEM THROUGH," Trump tweeted. "Big danger. Nancy and Chuck must approve Boarder Security and the Wall!"

Trump's rapid-fire tweets came the night before Mueller's deadline to submit documents outlining what the special counsel's office has described as the former Trump campaign chairman Paul Manafort's "crimes and lies," including allegations he lied in violation of his plea deal with the special counsel. Manafort agreed to cooperate with the special counsel while pleading guilty to one count of conspiracy to obstruct justice and one count of conspiracy against the US in September.

Trump followed up with a series of five tweets on Friday morning in which he repeated his common refrain that the Russia investigation was a "witch hunt" and accused Mueller of having multiple conflicts of interest, including being "Best Friends" with former FBI Director James Comey, who was set to testify to Congress on Friday.

The special counsel's team also Friday was expected to submit its sentencing recommendation for the former Trump attorney Michael Cohen, who has pleaded guilty to financial crimes and, more recently, lying to Congress.

Mueller's office released a similar recommendation this week for the former national security adviser Michael Flynn, who cooperated with investigators after pleading guilty to lying to the FBI.

Trump's tweets on Friday morning Trump targeted Andrew Weissmann, a prosecutor on the special counsel Robert Mueller's team. Trump accused Weissmann of having a "horrible and vicious prosecutorial past" and said he "wrongly destroyed people's lives" — referring to a conviction he made against an Enron auditor that was later overturned by the Supreme Court.

Trump also accused members of Mueller's team of having made donations to Hillary Clinton's presidential campaign and asked whether it would be included in Mueller's report. He also revived his talking points alleging corruption in the Democratic National Committee and on Clinton's campaign.