(Reuters) - Former Turing Pharmaceuticals Chief Executive Officer Martin Shkreli on Thursday called members of the U.S. Congress “imbeciles” on Twitter, moments after he refused to testify before a House of Representatives committee on why his company raised the price of a lifesaving medicine 5,000 percent.

Martin Shkreli, former CEO of Turing Pharmaceuticals LLC, prepares to testify before a House Oversight and Government Reform hearing on "Developments in the Prescription Drug Market Oversight" on Capitol Hill in Washington February 4, 2016. REUTERS/Joshua Roberts

“Hard to accept that these imbeciles represent the people in our government,” said Shkreli, using his @MartinShkreli Twitter handle.

He added, “I had prior counsel produce a memo on facial expressions during congressional testimony if anyone wants to see it. Interesting precedence.”

Earlier, Shkreli invoked his Fifth Amendment right against self-incrimination and declined to answer questions from lawmakers about drug price increases he engineered such as hiking the price of 62-year-old Daraprim to $750 a pill from $13.50.

During the hearing, Shkreli, whose youth and attitude have prompted some critics to label him “Pharmabro,” responded to questions by continuing to laugh, twirling a pencil and yawning.

After his appearance, he also retweeted several posts from supporters, including one from Michael J Lis (‏@mikeylis) that said: “Congress should just ask @MartinShkreli questions on Twitter instead of putting them in front of the house committee.”

Shkreli, 32, sparked outrage last year among patients, medical societies and Democratic presidential front-runner Hillary Clinton after the big hike in the price of 62-year-old Daraprim.

Shkreli was a trending topic on social media following the hearing. There are about 30 posts per minute about him on Twitter as of Thursday morning, according to analytics firm Zoomph. About 92,000 people were talking about Shkreli on Facebook.

His appearance prompted outrage on Thursday from members of Congress. Bernie Sanders (@BernieSanders), U.S. senator from Vermont and Democratic presidential candidate, tweeted, “The American people are fed up with the blatant profiteering of pharmaceutical company CEOs like Martin Shkreli. It must end.”

U.S. House Representative from New Mexico Michelle Lujan Grisham (@RepLujanGrisham), a Democrat, said: “With all of the smirking, does @MartinShkreli really take this issue seriously? #PharmaBro.”