WASHINGTON (Reuters) - A senior Democrat on a congressional panel seeking President Donald Trump’s tax returns warned on Saturday that the current Congress may not see the long-sought tax documents without launching an impeachment inquiry.

FILE PHOTO: U.S. President Donald Trump arrives for an event on healthcare coverage options for small businesses and workers in the Rose Garden of the White House in Washington, U.S., June 14, 2019. REUTERS/Leah Millis/File Photo

Representative Lloyd Doggett, who sits on the House Ways and Means Committee, said Democrats, who control the House of Representatives, were slow to request Trump’s tax returns from the Internal Revenue Service and now need to push back forcefully against Trump’s refusal to turn over the returns.

“Because this request was delayed until April and no legal action has yet been filed to get the returns, it is certain we won’t get them this year and perhaps (will face) some challenge to even get them with favorable expedited rulings by the time this Congress ends,” Doggett, who chairs the House Ways and Means health subcommittee, told CNN.

“That and the total obstruction by Trump have convinced me that we need to institute an impeachment inquiry,” the Texas Democrat said. “I just think we need a thorough investigation and a strong pushback immediately to a president who believes he’s above the law.”

The current Congress is due to end in January 2021.

House Ways and Means Chairman Richard Neal requested six years of Trump’s individual and business tax returns on April 3, under a federal law that says the Treasury secretary “shall furnish” such documents if requested by a lawmaker who holds in Neal’s position. He later subpoenaed the returns.

Treasury Secretary Steven Mnuchin rejected the subpoena. On Friday, the Justice Department issued a legal opinion saying the secretary was on solid ground for doing so.

Neal has said he is likely to sue in federal court to enforce the subpoena and obtain the returns. But he has taken no such action.

Democrats want Trump’s returns as part of their inquiry into possible conflicts of interest posed by his continued ownership of extensive business interests, even as he serves as president.

Trump has broken with a decades-old precedent among recent U.S. presidents by refusing to release his tax returns while a presidential candidate in 2016 or since being elected, saying he could not do so while his taxes were being audited.

Numerous tax experts have said an audit should not be an obstacle to disclosing his returns.