An Israeli law center said Thursday it is threatening to sue Twitter unless the social network cuts off access to groups, including Hezbollah, that are considered terrorist organizations by the United States.

The law center, Shurat HaDin, describes itself as being “dedicated to enforcing basic human rights through the legal system,” and says it has represented “victims of terrorism in courtrooms around the world.”

In a letter to San Francisco-based Twitter, attorney and Shurat HaDin executive director Nitsana Darshan-Leitner wrote that “it has come to our attention that Twitter, Inc. provides social media and associated services” to such groups as Hezbollah and the Al-Qaeda-affiliated Al-Shabaab — labeled as “foreign terrorist organizations” (or FTOs) by the United States.

“Please be advised that providing social media and other associated services to terrorist groups is illegal and will expose Twitter, Inc. and its officers to both criminal prosecution and civil liability to American citizens and others victimized by terrorisms carried out by Hezbollah, Al-Shabaab or other FTOs.”

Shurat HaDin specifically contends that Twitter’s service goes against a 2010 Supreme Court case declaring unlawful “any assistance or support” to terrorist organizations.

The law center, which has a New York office, wants Twitter to “immediately provide us written confirmation” that it will “permanently” discontinue access to Hezbollah, “Al-Manar TV, Al-Shabaab and any other FTOs … Absent such confirmation, we will seek all available relief and remedies against Twitter, Inc. in all relevant jurisdictions.”

A spokesman for Twitter said the company does not have any comment about the potential lawsuit or the issue of allowing access to the groups. But it has long made a point of saying it does not take political sides, and favors free speech.

READ MORE: MSNBC