"It is against the Twitter Terms of Service to use the service to commit illegal acts. Threatening the life of the president (or president-elect) is a federal offense under Title 18, USC, section 871. All accounts in violation of our Terms of Service are permanently suspended and we report to legal authorities accordingly."
Twitter did not immediately return messages for comment by ABC News.com.
The tweeted threats come on the heels of increasingly-heated rhetoric by some conservatives aimed at Democratic lawmakers working on health care reform, even as the Secret Service says threats against the president are declining.
On their way into the House over the weekend, protesters yelled racial and homophobic epithets at entering Congressmen.
Earlier this month Secret Service Director Mark Sullivan told a House committee that assassination threats against the president had declined sharply since their peak during the 2008 election.
"We have a program area that is just dedicated to protective intelligence I believe we are very aggressive with it," Sullivan said. "Every day there is somebody out there that is looking to harm those people that we protect, and you're right it could be a lone gunman it could be an organized group and we have to look at every single one of those possibilities."