President Donald Trump is reportedly calling his former advisers at night to talk about his poll numbers for the 2020 US presidential election, according to a New York Times report.

The president reportedly takes aim at former Vice President Joe Biden, one of the Democratic frontrunners, during these personal calls to his old associates, some who have not talked to Trump for years.

Trump, who is 72 years old, reportedly described Biden, who is 76 years old, as "too old" and "not as popular as people think" — despite some polls showing Biden leading with a slight edge in Republican-leaning states.

Trump's interest in campaign planning oscillates between being disinterested and micro-managing it, The Times reported.

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President Donald Trump is reportedly calling his former advisers at night to talk about his poll numbers for the 2020 US presidential election, according to a New York Times report published Monday.

The president reportedly jabs former Vice President Joe Biden, one of the Democratic frontrunners, during these personal calls to his old associates, some who have not talked to Trump for years.

Trump, who is 72 years old, reportedly described Biden, who is 76 years old, as "too old" and "not as popular as people think" — despite some polls showing Biden leading with a slight edge in Republican-leaning states.

Trump was reportedly briefed on an alarming 17-state internal poll that showed him polling behind Biden in some crucial states, and then told aides to deny the numbers after details of it leaked.

Biden's presidential bid has been a worrisome threat, sources familiar with Trump's thinking previously said in an Axios report. Trump was reportedly worried about Biden's appeal to working class white voters and the potential for Pennsylvania, Biden's home state, to flip in his opponent's favor.

Trump's rhetoric towards Biden has escalated in recent weeks. Trump described Biden has having "low IQ" and repeated several nicknames he has of the former vice president. Trump mocks Biden in tweets and during campaign speeches, often referring to him as "sleepy" or "crazy."

Read more: Trump's campaign reportedly considered copying his iconic Trump Tower escalator ride to kick off his re-election campaign

Trump's interest in campaign planning oscillates between being disinterested or micro-managing, The Times reported. At times, Trump appeared to be distracted and primarily focused on his approval numbers.

In other instances, Trump reportedly insisted on approving the songs played on his campaign, as well as the merchandise.

Trump raised over $30 million between January and March, and has a goal of raising $1 billion for the upcoming race. Trump's 2016 campaign raised over $957 million (over four-hundred million short of Democratic presidential candidate Hillary Clinton's fundraising total), according to The Washington Post.