The Manhattan District Attorney's office has subpoenaed Trump's accountants for the returns.
Lawyers for President Donald Trump want the Supreme Court to block New York prosecutors from obtaining his tax returns.
"We have filed a petition with the U.S. Supreme Court seeking to overturn the 2nd Circuit decision regarding a subpoena issued by the New York County District Attorney. The 2nd Circuit decision is wrong and should be reversed," Trump attorney Jay Sekulow told NBC News late Thursday afternoon.
The Manhattan D.A. subpoenaed Trump's tax preparer, Mazars USA, for eight years of his personal and business tax returns earlier this year as part of an investigation into pre-election payoffs to two women who alleged they'd had affairs with Trump.
Trump's lawyers filed suit to block the move, arguing that state authorities cannot investigate a sitting president. A Manhattan federal court judge sided with the D.A., and Trump's lawyers appealed to the 2nd Circuit Court of Appeals, whichruled against the president earlier this month.
"There is no obvious reason why a state could not begin to investigate a president during his term and, with the information secured during that search, ultimately determine to prosecute him after he leaves office," the appeals court ruling said.
Prosecutors from D.A. Cyrus Vance's office had agreed to give Trump's team time to appeal to the Supreme Court before they try to enforce the subpoena. The delay will remain in effect until the high court either declines to hear the case or issues an opinion.
"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," Sekulow said.
Because the tax documents were requested under a grand jury subpoena, it's unlikely they will become public if turned over. Trump is engaged in a series of legal battles across the country to keep his tax returns private. He is the first president to refuse to voluntarily make his tax returns public since Richard Nixon, who begrudgingly released them in 1973.