A top Democrat called President Trump the "worst president in modern history" after Trump said he would roll back Obamacare "piece by piece."

"Latest reason why President Trump is the worst President in modern history: Deliberately undermining people's health care out of spite," Rep. Adam Schiff, D-Calif., tweeted Friday morning.

The White House released a statement late Thursday saying it intended to end insurance subsidies under Obamacare that help low-income people pay for out-of-pocket costs.

"The government cannot lawfully make the cost-sharing reduction payments," White House press secretary Sarah Sanders said in a statement, citing guidance from the Department of Justice and the Department of Health and Human Services.

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Earlier Thursday Trump signed an executive order to loosen some Obamacare requirements to make it easier for people to buy less expensive, but less comprehensive, healthcare plans.

"Obamacare is a broken mess. Piece by piece we will now begin the process of giving America the great HealthCare it deserves!" Trump wrote Friday morning.