President Donald Trump slammed former President Barack Obama's campaign, citing a report that it paid nearly $1 million to a law firm linked to the company behind the controversial and unverified dossier alleging connections between Trump and Moscow.

His comments came in the form of a tweet on Monday morning:

Report out that Obama Campaign paid $972,000 to Fusion GPS. The firm also got $12,400,000 (really?) from DNC. Nobody knows who OK'd! — Donald J. Trump (@realDonaldTrump) October 30, 2017

According to a report by The Federalist, Obama's campaign organization paid $972,000 to Perkins Coie, the law firm that had funneled money to Fusion GPS, the company behind the dossier.

The Washington Post had reported that Hillary Clinton's campaign and the Democratic National Committee helped fund the research that resulted in the dossier. A lawyer from Perkins Coie represented the Clinton campaign and the DNC and retained Fusion GP to conduct the research, The Post said.

But a Federal Election Commission report reveals that Obama For America, paid nearly $800,000 to Perkins Coie in 2016 for "legal services," The Federalist reported. Another $174,725 was paid by OFA to the law firm in 2017.

The Federalist noted the timing of the payments to the law firm raise questions where the OFA money was eventually winding up. OFA was responsible for Obama's successful 2012 re-election campaign. It reorganized after the 2016 election and planned to use its resources to oppose Trump, the Federalist said.

The New York Times reported the law firm was paid $12.4 million to represent the Clinton campaign and the DNC during the campaign in 2016.