WATCH: Big Tech hearing quickly gets heated as congressman grills CEOs over Capitol riot and anti-vaxxers

A hearing featuring major tech CEOs on Thursday quickly grew heated as Rep. Mike Doyle (D-PA) grilled them over their platforms' roles in spreading misinformation about the 2020 presidential election and COVID-19 vaccinations.

Doyle began the hearing by asking Facebook CEO Mark Zuckerberg "if your platform bears some responsibility for disseminating disinformation related to the election and the stop the steal movement that led to the attack on the Capitol."

Zuckerberg, however, refused to give a straightforward answer and instead only said that "our responsibility is to make sure that we build effective systems."

Google CEO Sundar Pichai similarly refused to give a straightforward answer, while Twitter CEO Jack Dorsey did take responsibility for the spread of election misinformation, but also said that "you also have to take into consideration the broader ecosystem" because "it's not just the technology platforms that are used."

Doyle also grilled Zuckerberg over a new study claiming that 73 percent of misinformation about vaccines spread on Facebook comes from just 12 different accounts.

"Why, in the midst of a global pandemic that has killed over half a million Americans, that you haven't taken these accounts down that are responsible for the preponderance of vaccine disinformation?" he asked. "Will you all commit to taking these platforms down today?"

"Congressman, yes, we do have a a policy..." Zuckerberg began.

"I know you have a policy, but will you take the sites down today?" Doyle replied.

"Congressman, I will need to look at -- have our team look at..." Zuckerberg continued.

"Have an answer for me tomorrow," Doyle shot back.

Watch the video below.