President Donald Trump called Chelsea Manning an “ungrateful traitor” on Twitter early Thursday, after a column by Manning criticized former President Barack Obama.

"Ungrateful TRAITOR Chelsea Manning, who should never have been released from prison, is now calling President Obama a weak leader. Terrible!" Trump tweeted.

Before leaving office, Obama commuted Manning’s 35-year sentence for sharing classified information to WikiLeaks when he was a U.S. Army private known then as Bradley Manning.

"The one simple lesson to draw from President Obama's legacy: do not start off with a compromise," Manning wrote in an op-ed in The Guardian. "They won't meet you in the middle. Instead, what we need is an unapologetic progressive leader."

The column went on to say, "Barack Obama left behind hints of a progressive legacy. Unfortunately, despite his faith in our system and his positive track record on many issues over the last eight years, there have been very few permanent accomplishments."

Manning was convicted in July 2013, of violations of the Espionage Act, among other offenses.