A migrant sits with his children as they wait to hear if their number is called to apply for asylum in the United States, at the border on January 25, 2019, in Tijuana, Mexico. (AP Photo)

An estimated 600,000 migrants who entered the US since March 2021 may be facing serious legal problems as the Biden administration released them without providing them with any charging documents or issuing dates to appear before the court, NBC News reported on Friday.

"Nearly 600,000 migrants who crossed the US border since March 2021 have been released into the United State without being charged or given a date to appear in court, thousands have even been dropped from the program that was supposed to track them," the report said.

According to the report, the Biden administration had annulled a policy on March 2021 that required migrants to be provided charging documents with a court date by Customs and Border Protection shortly after they were apprehended.

Due to this, several migrants are now scattered across the US without a court date to determine whether they can remain in the country.

While the one-year eligibility deadline to apply for asylum for some is nearing expiry, many remain confused as to how to proceed with the next steps.

More than 800,000 migrants were released on Notices to Report or Parole Plus ATD between late March 2021 and late January 2023. Likewise, about 214,000 were issued charging documents with court dates, the report states.

On January 28, former President Donald Trump vowed to penalize future administrations that would allow migrants to cross into the country if he is re-elected.

He vowed to restore security measures at the border that were instated during his presidency and will ask Congress to impose criminal penalties on future administrations for allowing migrants in the US.

"Within hours of my inauguration we will restore every border security measure of the Trump presidency, we had it so good, to quickly achieve the most secure border in US history again, just as we had two years ago. And I will ask Congress to establish criminal penalties for any future administration that releases millions and millions of people that you do not want in our country," Trump said in a keynote speech at New Hampshire Republican annual meeting.

Since President Joe Biden assumed office in January 2021, the US has witnessed two consecutive years of illegal crossings reaching an all-time high.

In the year 2022 alone, the US Customs and Border Protection recorded an estimated 2,000,000 illegal crossings.