Concord, New Hampshire - President Joe Biden waded into fraught political territory Tuesday with an off-the-cuff remark about political opponent Donald Trump, saying that to block the Republican presidential candidate's radical proposals, "we got to lock him up."

"Politically lock him up," Biden quickly added after some applause from the crowd at a New Hampshire campaign office.

With Trump facing multiple pending criminal charges as he competes against Vice President Kamala Harris to succeed Biden, the White House has been very careful not to weigh in on the Republican's legal problems.

Trump has repeatedly claimed that the charges – some of which revolve around his efforts to overturn his 2020 loss to Biden – were only brought to hamstring him politically.

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When Trump faced off against Hillary Clinton in 2016, the businessman-turned-politician called for his Democratic opponent to be investigated and imprisoned, with rowdy crowds frequently breaking into chants of "lock her up."

The chant was seen as a major break in political norms at the time, and though Trump eventually achieved a stunning upset victory over Clinton, she was never charged with any crime.

The Trump campaign was quick to seize on Biden's comments as supporting its claim of bias against its candidate.

"Joe Biden just admitted the truth: he and Kamala's plan all along has been to politically persecute their opponent, President Trump, because they can't beat him fair and square," said Karoline Leavitt, the campaign's national spokesperson.

Crowds at several Harris rallies have broken out into chants of "lock him up," but the vice president has been quick to push back.

"Hold on," the vice president said, interrupting chants at a rally earlier this month. "The courts will handle that. Let's handle November, shall we?"

With just two weeks until the November 5 election, both Trump and Harris remain neck-and-neck in polling.