Donald Trump has ordered his incoming director of national intelligence (DNI) to start purging officials from the Obama and Biden administrations.

The President told Tulsi Gabbard's replacement, Bill Pulte, that the 18 agencies, including the CIA and FBI, that he now oversees are 'unnecessary and/or too big.'

Trump told the Wall Street Journal: 'I'd like to see it smaller. I think there are a lot of people in there that shouldn't be there.'

The President told reporters he wants Pulte, a former Florida real estate executive, to 'start the process' of firing people, even though he is only serving on an acting basis. 

Pulte's extraordinary elevation this week from the Director of the Federal Housing Finance Agency to the country's top intelligence official sparked backlash among Republican lawmakers on Capitol Hill.

But he will avoid a Senate confirmation process by serving in an acting capacity.

'You're less shackled,' Trump said of Pulte's status. 'It sort of gives you more power, you know, for a somewhat limited period of time.'

Trump added that he plans for Pulte to make the intelligence purge before he picks a permanent intelligence chief.

'Frankly, it might be good for him to shake it up before people come,' Trump added.  

'Because, if he [Pulte] reduced the size, in conjunction with me… and in conjunction with possibly the person coming in… he can do a lot of the hard work and we wouldn't have to saddle somebody that goes in.' 

Pulte, in his role, will brief the President on the most classified areas of intelligence and has control of more than $100 billion in annual budget for various agencies. 

The job also gives Pulte the power to declassify vast numbers of secret documents. 

Trump told the Wall Street Journal he wants Pulte to release more classified documents related to the 2020 election and his claims of voter fraud.

'I would say everything - he should look at everything and make a determination,' Trump said.

Pulte has been angling for the job in recent weeks, following Gabbard's sudden resignation due to her husband's rare bone cancer.

He told Trump he would be loyal and would carry out his directives to the intelligence community.

It is unclear when Trump's mass firings will occur, or whether they already have.

A spokesman for the Office of the Director of National Intelligence said: 'We look forward to working with Mr Pulte and President Trump on additional initiatives to advance savings and root out deep state bad actors.'