Hunter Biden, the son of U.S. President Joe Biden was criminally charged with weapons violation as a drug addict.

Hunter Biden, 53, is accused of concealing his drug use during a gun purchase in 2018.

A planned plea deal with the Delaware Attorney General's Office on the charges had previously fallen through.

Former U.S. President Donald Trump, expected to be Joe Biden's rival again in next year's presidential election, is facing four separate criminal trials at present.

His son Donald Trump Junior posted on X: "Now that Hunter Biden has been indicted how many mins till Biden's corrupt DOJ (Department of Justice) drops another Trump indictment to change the narrative?

"It's nice to see something happen, though this is likely the excuse DOJ will use to pretend they're fair when they give him slap on the wrist!"

The tax investigation into Biden remains ongoing, after Special Counsel David Weiss previously said any possible charges would need to be brought in either the District of Columbia or the Los Angeles-based Central District of California.

The move comes two days after House of Representatives Republicans opened an impeachment inquiry of Joe Biden related to Hunter Biden's foreign business dealings. The White House has denounced that step, made without a vote by the full House, as unsubstantiated and politically motivated.

"As expected, prosecutors filed charges today that they deemed were not warranted just six weeks ago following a five-year investigation into this case," Hunter Biden attorney Abbe Lowell said in a statement. "The evidence in this matter has not changed in the last six weeks, but the law has and so has MAGA Republicans' improper and partisan interference in this process."

The White House declined to comment. A spokesperson for Weiss declined to comment.

Some legal experts have said that any firearms-related charges against Biden could be vulnerable to a constitutional challenge after the U.S. Supreme Court last year in a landmark ruling expanded gun rights under the U.S. Constitution's Second Amendment, which protects the right to bear arms.