WASHINGTON – President Donald Trump used a relatively rare signing statement Friday to object to portions of the $2 trillion coronavirus stimulus law, potentially opening a new front with Democrats on the oversight of how that money is spent.

Trump said he would ignore portions of the law demanded by some Democrats to give Congress additional visibility into the stimulus spending, arguing that those requirements would infringe on the separation of powers enshrined in the Constitution.

Congress and the White House moved with stunning speed to pass the massive economic stimulus, the largest in the nation's history, in an effort to avoid economic calamity from the coronavirus. But now that the measure is law, the administration must shell out hundreds of billions of dollars quickly while attempting to avoid controversy.

"It is a big deal," said Danielle Brian with the Project On Government Oversight. "I'm hoping that, given the crisis, Congress will realize this is a line that must not be crossed."

A signing statement is a written pronouncement from a president when a bill is signed into law. The document can be used to explain a president's position, prod Congress to pass more legislation, or to put the president on record raising constitutional issues. But the practice has drawn fire from watchdog groups who say presidents have used the documents to rewrite portions of laws they disagreed with rather than vetoing them.

Brian said Congress has acquiesced to the statements since before the Trump administration, but she said they have no legal meaning, and she urged lawmakers to push back against efforts to undermine congressional oversight of the spending.

"Americans expect and deserve accountability for the $2 trillion coronavirus emergency spending bill, and Congressional oversight of this Administration’s handling of the funds is absolutely critical," Common Cause President Karen Hobert Flynn said in a statement.

"This attempt by President Trump to bypass oversight is nothing more than a corrupt power grab by an administration known for bending over backwards to shower rewards on its political supporters," she added.

Democrats balked at what they saw as a lack of oversight provisions in the initial draft of the measure. Trump drew attention this week when, responding to questions about those concerns, he declared that, "I'll be the oversight." Lawmakers ultimately OK'd several new entities, including a new inspector general, to monitor the law's implementation.

More:Trump signs $2 trillion coronavirus stimulus intended to halt economic meltdown

The legislation, designed in part to help businesses and corporations hammered by closures due to the coronavirus pandemic, creates multiple layers of accountability for the billions of dollars in loans, grants and direct cash that will soon flow from the federal government. The House passed the bill by voice vote on Friday and Trump immediately signed it.

President Barack Obama faced similar concerns after the approval of the American Recovery and Reinvestment Act in 2009. Republicans pilloried the nearly $800 billion effort, arguing it was full of "wasteful government spending." Several GOP lawmakers produced lists highlighting examples they thought were particularly egregious.

Neither House Speaker Nancy Pelosi, D-Calif., nor Senate Minority Leader Chuck Schumer, D-N.Y., immediately responded to questions about Trump's statement.

“It’s not a surprise to anyone,” Pelosi said of the president’s signing statement on MSNBC. “Congress will exercise its oversight.”

A Democratic aide speaking on the condition of anonymity to discuss internal strategy said Democrats anticipated the president’s move “so that’s why there are multiple layers of strict oversight in this bill.” The aide pointed to a congressional oversight commission created by the law in addition to the special inspector general and other provisions.

The coronavirus stimulus package, which will send millions of Americans and businesses direct payments or loans, creates several new oversight entities.

The law requires the leaders of a newly created Pandemic Response Accountability Committee to be appointed by the Council of the Inspectors General on Integrity and Efficiency with the consultation of congressional leaders. The council is an independent agency within the executive branch and Trump said in his statement that requiring it to consult with Congress to fill the roles represents an overreach.

Trump wrote that he anticipates consultation would take place, but that it shouldn't be a requirement.

Another section creates a special inspector general for pandemic recovery within the Treasury Department. The new law requires that person to report to Congress if an agency in the administration denies a document request. Trump said he would not treat the provision as allowing the inspector general to issue reports to Congress without "presidential supervision."

Trump said that other provisions of the law appear to condition the ability of federal agencies to spend money on consultation with congressional committees.

"These provisions," Trump wrote, "are impermissible forms of congressional aggrandizement with respect to the execution of the laws."

Trump said he would "make appropriate efforts to notify the relevant committees" before taking the actions called for in the law but would not treat "spending decisions as dependent on prior consultation with or the approval of" Congress.