President Donald Trump is bashing Democrats for questioning the timing and scope of the FBI probe into the sexual allegations against Supreme Court nominee Brett Kavanaugh.

'Wow! Just starting to hear the Democrats, who are only thinking Obstruct and Delay, are starting to put out the word that the 'time' and 'scope' of FBI looking into Judge Kavanaugh and witnesses is not enough. Hello! For them, it will never be enough - stay tuned and watch!,' the president tweeted on Sunday afternoon.

His tweet came shortly before former FBI director James Comey published an op-ed in The New York Times about what the agency was being asked to do, writing 'the F.B.I. is up for this. It’s not as hard as Republicans hope it will be.'

President Donald Trump is bashing Democrats for questioning the timing and scope of the FBI probe into the sexual allegations against Supreme Court nominee Brett Kavanaugh

'F.B.I. agents are experts at interviewing people and quickly dispatching leads to their colleagues around the world to follow with additional interviews. Unless limited in some way by the Trump administration, they can speak to scores of people in a few days, if necessary,' Comey wrote.

'They will confront people with testimony and other accounts, testing them and pushing them in a professional way. Agents have much better nonsense detectors than partisans, because they aren’t starting with a conclusion,' he added.

Comey dismissed concerns about how long ago the incident took place, writing agents know that 'Significance drives memory. They also know that little lies point to bigger lies. They know that obvious lies by the nominee about the meaning of words in a yearbook are a flashing signal to dig deeper.'

And Trump's tweet comes as Democrats have raised concerns about the limited number of witnesses being questioned by the FBI and as Trump officials claim the White House is not 'micromanaging' the probe.

Democratic Sen. Amy Klobuchar of Minnesota has expressed concern over reports the White House is limiting the scope of the FBI investigation

Democrats like Sen. Amy Klobuchar of Minnesota have expressed concern over reports that only four witnesses will be questioned by the FBI in their investigation at the direction of the White House.

'What we are hearing are reports that they are trying to limit this,' Klobuchar said on CNN's 'State of the Union' Sunday. 'I'm very concerned about this because the White House should not be allowed to micromanage an FBI investigation.'

She expressed concern some people who knew Kavanaugh when he was at Yale University would not be interviewed about their recollections of him drinking, some of whom claim he drank to excess at times.

'You have these other people from parts of his life who have said that he was belligerent when he was drunk and other things. Now, they have not been interviewed by the FBI,' she said.

Democratic Sen. Mazie Hirono said she hoped the investigation wasn't a farce.

'To limit the FBI as to the scope and who they're going to question, that really – I wanted to use the word farce, but that's not the kind of investigation that all of us are expecting the FBI to conduct,' she said Sunday on ABC's 'This Week.'

Both Klobuchar and Hirono sit on the Senate Judiciary Committee and questioned Kavanaugh on Thursday. Klobuchar specifically asked him about his drinking, including if he had ever drunk so much he 'didn't remember what happened the night before or part of what happened.'

White House press secretary Sarah Sanders said the administration is not micromanaging the FBI investigation into the allegations against Brett Kavanaugh

'You're asking about blackout. I don't know, have you?' Kavanaugh responded.

'Could you answer the question, judge?' Klobuchar said.

She told CNN she was 'stunned' at his behavior.

'I was really stunned by how he acted at that hearing. This is basically a job interview for the highest court of the land,' Klobuchar said.

Meanwhile, White House officials took to the Sunday morning shows to defend the investigation, saying it was being done at the direction of the Senate.

White House press secretary Sarah Sanders vowed the administration 'is not micromanaging' the FBI investigation into the charges against the Supreme Court nominee.

'The White House is not micromanaging this process. The Senate is dictating the terms,' Sanders said on 'Fox News Sunday.'

Republican Sen. Lindsey Graham said Kavanaugh is not a 'stumbling bumbling drunk gang rapist' so there is no need to question his college classmates about his drinking

Questions have arisen about who the FBI will be speaking to in its probe, particularly if investigators will question Julie Swetnick, who has accused Kavanaugh and his Georgetown Prep friend Mark Judge of being part of a group of boys that drugged and raped women.

Agents are going to interview Judge as they investigate Christine Blasey Ford's allegation that Kavanaugh held her to a bed, tried to take off her clothes and covered her mouth when she screamed when they were at a high school party in the 1980s.

Judge will also be questioned about Swentick, according to reports.

Kavanaugh as denied all allegations against him.

Then there are the questions as to why the FBI won't speak to Kavanaugh's high school and college classmates who have said in interviews with reporters that Kavanaugh drank heavily, including some who claimed he drank to excess.

White House counsel Don McGahn, working with Senate Republicans, came up with the list of four witnesses: Judge; Leland Keyser, a high school friend of Ford's whom she said attended the high school party in question but was not told of Kavanaugh's alleged assault on Ford; P.J. Smyth, another guest at the high school party; and Debra Ramirez, who charged Kavanaugh with exposing himself to her during a college party when they were both students at Yale University, thrusting his penis in her face and forcing her to touch it when she pushed him away.

Sanders said she's not aware if McGahn has given the FBI a witness list of who agents can and cannot talk to.

White House counselor Kellyanne Conway reiterated the administration would not interfere in the investigation

'The White House counsel has allowed the Senate to dictate what these terms look like and what the scope of the investigation is. Again, the White House isn't intervening, we are not micromanaging this process. This is a Senate process, it has been from the beginning. We are letting the Senate continues to dictate what the terms look like,' she said.

She said it was up to the Senate if Swetnick was to be interviewed.

'That's a question you would have to ask the Senate. That's not something the White House is engaging in,' Sanders said on Fox.

But, she cautioned, the FBI investigation will not become a fishing expedition.

'This can't become a fishing expedition like the Democrats would like to see it be,' she said.

Trump insisted on Saturday the FBI has been given 'free rein' in the reopened probe, writing in a tweet: 'I want them to interview whoever they deem appropriate, at their discretion.'

And Republican Sen. Lindsey Graham said Kavanaugh is not a 'stumbling bumbling drunk gang rapist' so there is no need to question his college classmates about his drinking.

'I think you're trying to portray him as a stumbling bumbling drunk gang rapist who during high school and college was Bill Cosby. Six FBI background checks over the years would have uncovered this,' Graham said on ABC's 'This Week,' when asked why the FBI would not be interviewing Yale University students who claimed to have seen Kavanaugh binge drinking.

Graham repeated his defense when he was asked a second time if Kavanaugh's school contemporaries should be interviewed.

Democratic Sen. Mazie Hirono said she hoped the investigation wasn't a farce

'He has had six FBI background checks. He has been on the political stage for 26 years. He's not a stumbling, bumbling drunk. I don't believe that you could accomplish what he has accomplished, to have been a serial rapist in high school, and stop it for the rest of your life,' he said.

Sanders also went on the attack, echoing a Republican charge against Democrats and Sen. Dianne Feinstein, the ranking Democrat on the Senate Judiciary Committee, that they knew about Ford's allegation but didn't make it handle it as they should have.

'Dianne Feinstein and her staff knew about these accusations. If they could have done all of this in a private way to protect Dr. Ford. Instead, for the people that claim to champion women, Democrats have exploited Dr. Ford, have exploited this process and I think it's been totally disgraceful,' she said.

She said Ford's testimony before the committee on Thursday was 'compelling' and that she was obviously a victim of an attack but noted there was no proof it was Kavanaugh who was the perpetrator.

'Nobody could deny that her testimony wasn't compelling, that it wasn't impactful and certainly it appears something happened to this woman and I don't think there's anybody in America who would condone that or be okay with that,' Sanders said. 'I do think the big question is was that Brett Kavanaugh and I think based on his testimony and the information he provided you can easily come away and say it wasn't.'

She added: 'I don't think anyone of us can know 100 percent, but I think we have to look at the information that's provided. It is no doubt that her story is heartbreaking and it's heart wrenching to watch it. I've watched it a number of times. Again, I think you have to look at Brett Kavanaugh's testimony as well. Equally heartbreaking. Look at the destruction of his family, look at how this is played out.'

In their separate testimonies on Thursday, both Ford and Kavanaugh said they were '100 percent' certain of their stories.

Kavanaugh delivered a fighting end to his Senate testimony when asked directly if he was innocent of claims he tried to rape Ford or had any doubts about his integrity.

'100 per cent. Not a scintilla. Swear to God,' he said.

Ford recounted in her dramatic testimony how Kavanaugh pinned her to a bed, tried to take off her clothes and covered her mouth when she tried to scream during a high school party in the 1980s.

She dismissed theories a Kavanaugh-look-alike attacked her instead.

When asked her degree of certainty it was Kavanaugh, Ford leaned down into the microphone and said: '100 percent.'

And on CNN, Kellyanne Conway reiterated the administration would not interfere in the investigation.

'The White House is not getting in the FBI investigation that way. The president very much respects the Independence of the FBI and said feels, as he said last night, that they should look at anything in this limited scope,' she said on 'State of the Union.'