WASHINGTON (Reuters) - A leading Democrat in Congress asked the U.S. Treasury on Tuesday to advise lawmakers about when it intends to seek an increase in the U.S. debt ceiling, an issue that could become part of the debate over President Donald Trump’s border wall.

FILE PHOTO: A sign marks the U.S Treasury Department in Washington, U.S., August 6, 2018. REUTERS/Brian Snyder/File Photo

Representative Richard Neal, who chairs the tax committee in the House of Representatives, requested details about the Trump administration’s debt limit plans in a Jan. 29 letter to Treasury Secretary Steven Mnuchin.

Treasury officials received Neal’s letter and were reviewing it, a spokeswoman said.

The current limit on U.S. debt extends through March 1, and analysts say Congress will likely have to reinstate the ceiling at a level well above $20 trillion or risk a first-ever default that would damage U.S. credit. Treasury should be able to sustain government obligations for longer by taking various measures, while using cash on hand and incoming revenues.

“The United States must continue to pay all of its bills on time and in full. I look forward to hearing from you about what adjustment in the debt limit is needed,” Neal said in the letter to Mnuchin.

Neal’s House Ways and Means Committee released the letter as the debt limit showed signs of becoming embroiled in the debate over Trump’s demand for $5.7 billion for a wall along the U.S.-Mexico border, which led to a 35-day shutdown of about one-quarter of the federal government.

Congress and Trump reopened the government last week with a measure that will expire on Feb. 15, to give negotiators time to work out an agreement.

Republican Senator Lindsey Graham has urged Trump to consider the possibility of making the debt limit part of ongoing negotiations over border security, according to CNN.

The idea was quickly rejected by Democrats, who have accused Trump of using federal workers furloughed by the shutdown as “hostages” in his bid to win congressional approval for his border wall.

“The debt ceiling. No more hostages!” Senate Democratic leader Chuck Schumer told reporters. “That’s not a good idea. We ought to be negotiating to get an agreement.”

In his letter, Neal blamed Trump’s 2017 tax cuts for a significant drop in government revenue and warned that effects of the shutdown could cut revenue.