The U.S. Department of Homeland Security's monitoring of social media services could be a threat to civil liberties and online free speech, several lawmakers said during a hearing Thursday.

According to a report by a civil liberties group called the Electronic Privacy Information Center, or EPIC, DHS paid more than $11 million to General Dynamics for a system to keep an eye on Facebook and Twitter public posts, as well as comment threads on major news websites.

EPIC's report found that the system watches public social media posts for comments that "adversely reflect" on the government, and for responses to proposed government plans. EPIC tried to get information about the deal through a Freedom of Information request, but was denied. It then filed a successful lawsuit and was granted access to the specifics by DHS.

During Thursday's hearing, congressmen from both sides of the asile grilled DHS about the General Dynamics deal as revealed by EPIC's lawsuit. One Democratic representative, Jackie Speier of California, said she was "deeply troubled" by the arrangement.

The Department of Homeland Security "is not a political operation," she added.

Pennsylvania Republican Representative Patrick Meehan also expressed doubts about the plan.

"My guess is that the average American has no problem with other private individuals reading their commentary in online writings and postings in open forums, but may feel a bit of unease knowing the federal government may be doing the same thing," said Meehan.

Reps. Speier and Meehan elaborated on their concerns about the deal in a letter sent to DHS Thursday.

"Although there are clear advantages to monitoring social media to identify possible threats to our security, there are also privacy and civil liberties concerns implicit in this activity," they wrote. "With its domestic mission, the Department of Homeland Security needs to be mindful of the rights of the citizens of our country to express themselves online. Not only should guidance issued by the Department permit analysts to do their jobs identifying threats, but it should also be stringent enough to protect the rights of our citizens."

DHS Chief Privacy Officer Mary Ellen Callahan defended the agency.

According to Callahan, DHS' social media activity has been limited to public outreach, gaining "situational awareness" when disasters strike and helping law enforcement. She added that privacy rules meant they could only collect information on public officials and during "life or death" situations.

"It is the what, not the who, being identified," said Callahan.

Would you feel comfortable with the government monitoring your public social media posts? Sound off in the comments below.

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