Conservative think tank The Heritage Foundation said on Friday that it experienced a cyberattack earlier this week.

A person with knowledge of the cyberattack told TechCrunch that efforts at Heritage were underway to remediate the cyberattack, but said that it wasn’t immediately known what, if any, data was taken.

Politico, which first reported the news of the cyberattack on Friday, cited a Heritage official as saying the organization “shut down its network to prevent any further malicious activity while we investigate the incident.”

The news outlet quoted the Heritage official as saying that the cyberattack likely came from nation-state hackers, but did not provide evidence of the claim.

Heritage spokesperson Noah Weinrich declined to comment when reached by email on Thursday, and did not immediately respond to a request for comment when contacted by TechCrunch on Friday.

Founded in 1973, Heritage is based in Washington DC, and supports and lobbies on conservative issues. The foundation is highly influential in Republican politics. Think tanks are frequent targets of overseas cyberattacks and nation state-led espionage efforts for their connections to government and policy making, many of which are staffed by former U.S. administration officials.

Heritage was hit by a cyberattack in 2015 in which hackers stole internal emails and the personal information of its donors.