President Trump on Thursday said he has "NOTHING to do" with the "potential prosecution" of President-elect Joe Biden’s son, calling the fallout surrounding Hunter Biden’s confirmation that he is under federal investigation "very sad to watch."

"I have NOTHING to do with the potential prosecution of Hunter Biden, or the Biden family," Trump tweeted Thursday. "It is just more Fake News."

He added: "Actually, I find it very sad to watch!"

The president’s tweets come after reports surfaced this week that he was calling for the appointment of a special counsel to ensure the federal investigation into Hunter Biden continued under the Biden administration.

Republicans on Capitol Hill have called for the appointment of a special counsel to investigate the younger Biden’s foreign business dealings.

Hunter Biden, last week, confirmed he was under federal investigation for his "tax affairs."

A well-placed government source told Fox News that Hunter Biden is a subject/target of the grand jury investigation. According to the source, a "target" means that there is a "high probability that person committed a crime," while a "subject" is someone you "don't know for sure" has committed a crime.

The source said President-elect Biden is not a subject of any grand jury investigation at this time.

The source also tells Fox News that this investigation was predicated, in part, by Suspicious Activity Reports (SARs) regarding suspicious foreign transactions.

Another source familiar with the investigation tells Fox News that the SARs were regarding funds from "China and other foreign nations."

A Treasury Department official, who did not comment on the investigation, spoke broadly about SARs, telling Fox News that SARs are filed by financial institutions "if there is something out of the ordinary about a particular transaction."

The official told Fox News that the mere filing of a SAR does not mean there has been a criminal act, or violation of regulations, but it instead flags that a transaction is "out of the ordinary" for the customer. The official noted, though, that a SAR could be part of a money-laundering or tax investigation.

The investigation, according to a source familiar with the matter, began in 2018.

Two sources familiar with the investigation tell Fox News that the investigation includes looking at the laptop purportedly belonging to Hunter Biden.

In October, Fox News first reported that the FBI subpoenaed a laptop and hard drive purportedly belonging to Hunter Biden in connection with a money-laundering investigation in late-2019.

President-elect Biden on Wednesday said he is "confident" that his son has done nothing wrong.

Meanwhile, Attorney General Bill Barr earlier this month made public that he had separately appointed U.S. Attorney from Connecticut John Durham as special counsel to continue his investigation into the origins of the Trump-Russia probe.

Barr announced this week that he would be resigning from his post as attorney general on Dec. 23, before Inauguration Day.

Jeffrey Rosen will take the helm at the Justice Department as acting attorney general.