Two top Democrats in the House and Senate are asking Facebook and Twitter to investigate whether Russian bots and trolls were involved in a social media campaign calling for the release of a memo detailing what Republicans say are abuses of a government surveillance program during the presidential campaign.

Sen. Dianne Feinstein, D-Calif., the top Democrat on the Senate Judiciary Committee, and Rep. Adam Schiff, D-Calif., the top Democrat on the House Intelligence Committee, sent letters to Facebook CEO Mark Zuckerberg and Twitter CEO Jack Dorsey asking them to look into whether accounts tied to Russia were involved in the #ReleaseTheMemo social media campaign.

“These Russian efforts are intended to influence congressional action and undermine Special Counsel [Robert] Mueller’s investigation, which has already resulted in the indictments of two Trump campaign officials and guilty pleas from two others, who are both now cooperating with prosecutors,” Feinstein and Schiff wrote. “It is critically important that the Special Counsel’s investigation be allowed to proceed without interference from inside or outside the United States.”

The #ReleaseTheMemo hashtag spread on social media after Republican lawmakers started calling for the release of a four-page memo they said showed FISA abuses.

The House Intelligence Committee voted along party lines to allow all House members to read the memo, but some Republicans wanted the document released to the public.

An analysis from the German Marshall Fund’s Alliance for Securing Democracy found the social media campaign received a considerable boost from accounts tied to Russia.

“If these reports are accurate, we are witnessed an ongoing attack by the Russian government through Kremlin-linked social media actors directly acting to intervene and influence our democratic process,” Feinstein and Schiff wrote. “This should be disconcerting to all Americans, but especially your companies as, once again, it appears the vast majority of their efforts are concentrated on your platforms.”

The Democrats asked Twitter and Facebook to determine the frequency and volume of postings on #ReleaseTheMemo from accounts linked to Russian influence efforts, as well as how many users were exposed to the campaign by Russian operations.