US President Donald Trump speaks to reporters before leaving the White House in Washington D.C., the United States, on Oct. 25, 2019. (Photo by Ting Shen/Xinhua)

 
US President Donald Trump on Thursday asked the Supreme Court to block a subpoena demanding his accounting firm to turn over eight years of his tax returns to Manhattan prosecutors, the president's personal attorney Jay Sekulow said in a statement.

"We have filed a petition with the US Supreme Court seeking to overturn the Second Circuit decision regarding a subpoena issued by the New York County District Attorney," Sekulow wrote.

"In our petition, we assert that the subpoena violates the US Constitution and therefore is unenforceable," Sekulow said. "We are hopeful that the Supreme Court will grant review in this significant constitutional case and reverse the dangerous and damaging decision of the appeals court."

The federal appeals court ruled earlier to uphold a subpoena ordering Trump's accountants to hand his financial records over for investigation.

It's thought to be the first time that a US president's personal financial dealings have made their way to the nation's top court. If the justices agree to consider the case, it could determine whether any US president has blanket criminal immunity while in office, local analysts said.

However, the court could also decline to hear the case, effectively requiring the disclosure of his returns, according to local media reports.

The US Supreme Court now has five conservatives and four liberals.