New York Attorney General Barbara Underwood filed a lawsuit against President Trump, his foundation, and other Trump family members Thursday morning, and shortly after Trump took to Twitter vowing to fight it:

"The sleazy New York Democrats, and their now disgraced (and run out of town) A.G. Eric Schneiderman, are doing everything they can to sue me on a foundation that took in $18,800,000 and gave out to charity more money than it took in, $19,200,000. I won’t settle this case! ... Schneiderman, who ran the Clinton campaign in New York, never had the guts to bring this ridiculous case, which lingered in their office for almost 2 years. Now he resigned his office in disgrace, and his disciples brought it when we would not settle."

The Trump Foundation also sent out a statement condemning the suit:

"This is politics at its very worst ... The reason the Foundation was able to donate more than it took in is because it had little to no expenses. This is unheard of for a charitable foundation. The Foundation currently has $1.7 million remaining which the NYAG has been holding hostage for political gain ... The prior NYAG, who was recently forced to resign from office in disgrace, made it his stated mission to use this matter to not only advance his own political goals, but also for his own political fundraising. The acting NYAG's recent statement that battling the White House is 'the most important work (she) have ever done' shows that such political attacks will continue unabated."

Be smart: As the New York Times' Maggie Haberman points out, Trump also said he wouldn't settle the Trump University suit — he settled it. Go deeper: Read the lawsuit here.