President Donald Trump’s personal attorney and U.S. House lawyers said Tuesday they were unable to reach an agreement over how to proceed in the president’s bid to prevent federal lawmakers from seeking copies of his New York state tax returns.

The impasse threw further uncertainty into Trump’s push to bar House Democrats from seizing on a New York law, passed only weeks ago, that opened a path for lawmakers to request the tax returns from state finance officials. Trump, defying norms, has refused to release his state and federal tax returns, despite promises that he would do so.