House Speaker Nancy Pelosi speaks at a town hall in Arizona in 2018.

House Speaker Nancy Pelosi has announced a formal impeachment inquiry of President Donald Trump on Tuesday afternoon after meeting with Democratic lawmakers. For months, Pelosi has resisted calls for impeachment.

The announcement comes days after Director of National Intelligence Joseph Maguire declined to turn a whistleblower complaint over to Congress as required by law. Media outlets have reported that the whistleblower complaint alleges Trump leveraged foreign aid to try to pressure a foreign leader to investigate a political rival.

The US Senate unanimously passed a resolution stating that the whistleblower complaint should be turned over to the legislature’s Intelligence Committee.

Meanwhile, Trump has admitted to discussing a long-debunked allegation of corruption against the son of former Vice President Joe Biden with Ukraine president Volodymyr Zelensky in an August phone call. Trump blocked about $400 million in aid to Ukraine, prompting speculation that he intended to withhold the aid until Zelensky pledged to launch an investigation of Biden, who could be the Democratic nominee to face Trump in the 2020 election.

It is not clear that the whistleblower complaint deals directly with that phone call. Pelosi has given the administration a Thursday deadline to turn over the complaint.

As more and more Democratic politicians join the call for impeachment, Trump has promised to release the full transcript of the phone call with Zelenski.