WASHINGTON -- US Attorney General Merrick Garland on Friday appointed a special counsel for the probe into Hunter Biden, the son of US President Joe Biden, according to an Associated Press report.

David Weiss, the US attorney in Delaware who had already been probing Hunter Biden's financial dealings, was named by Garland as special counsel after plea deal talks in the case broke down, said the report.

The appointment of the special counsel is deemed as a significant development from typically cautious Garland, and provides Weiss with independence, authority and budget to pursue the investigation.

The US Department of Justice said in a June court filing that Hunter Biden, who has been under investigation by a federal grand jury since 2018, will plead guilty to two misdemeanor counts of failing to pay his 2017 and 2018 taxes on time.

However, prosecutors in Delaware announced Friday that the plea deal talks had hit an impasse.

Special counsels in the United States are typically appointed to investigate cases where the Justice Department perceives itself as having a conflict or where it's deemed to be in the public interest.