Speaker Nancy Pelosi (D-California) insisted that the whistleblower complaint about Trump’s conversation be addressed immediately, and threatened a “new stage of investigation” if the administration continues to block the complaint.

“This violation is about our national security,” Pelosi wrote in a letter to members of Congress on Sunday. “The Inspector General determined that the matter is ‘urgent’ and therefore we face an emergency that must be addressed immediately.”

She called for a bipartisan effort to “seek the truth to protect the American people and our Constitution.”

The complaint, which was made by a member of the U.S. intelligence community to the acting Director of National Intelligence, has been blocked from being shared with Congress. News outlets have reported that the complaint allegedly is about a phone conversation between President Donald Trump and the president of Ukraine.

House Intelligence Committee Chairman Adam Schiff (D-California) subpoenaed the complaint after he became aware of its existence, but the acting DNI refused to comply with the demand.

In a letter to Schiff, DNI general counsel Jason Klitenic wrote that the whistleblower statute requiring the DNI to turn over complaints to congress only applies to someone “within the responsibility and authority” of the DNI. He argued that because the whistleblower complaint was directed at a person outside of the intelligence community, the acting DNI is under no legal obligation to share it with Congress.

“The complaint here involves confidential and potentially privileged matters relating to the interests of other stake holders within the Executive Branch,” Klitenic wrote.

Pelosi’s call for an investigation contradicts her outspoken opposition to impeachment proceedings, but she hopes by making the complaint public, other whistleblowers will be less hesitant to come forward in the future.

“The Administration’s blocking of Acting DNI Maguire from providing Congress with the whistleblower complaint calls upon him to violate the federal statute, which unequivocally states that the DNI “shall” provide Congress this information,” wrote Pelosi. “The Administration is endangering our national security and having a chilling effect on any future whistleblower who sees wrongdoing.”