Representatives from Twitter have met with Senate staffers to discuss concerns about Russian-backed efforts to use the network to spread propaganda and misinformation to manipulate the U.S. election, both sides confirmed on Wednesday. The meeting was the result of a letter sent by Delaware Sen. Tom Carper, ranking Democrat on the Senate Homeland Security Committee, to Twitter CEO Jack Dorsey about the issue.

“These ‘social’ cyberattacks are made possible through the proliferation of ‘bots,’ automated and often false accounts controlled by a single entity, that pollute information streams by generating messages that appear to come from many different users,” Carper wrote last month in the letter to Dorsey, inquiring about steps the company takes to curb automated bots on the network.

“Our staff recently met with Senator Carper’s staff, to explain our content policies and anti-spam tools,” Twitter spokesman Nu Wexler wrote in an email to Fast Company Wednesday, though Wexler declined to comment further on the meeting or on any statistics the company may have on such bots on the network. A spokesperson for Carper also declined to comment, beyond saying that the senator’s staffers were “pleased to have a substantive meeting” with the Twitter representatives.

A report in The Guardian last year described a Russian state-sponsored “troll army,” paid to intersperse innocuous clickbait posts on blogs, forums, and social networks, with content praising Russian President Vladimir Putin and critiquing enemies of his regime at home and abroad.

Both Russian-funded official media, like the RT television network, and government-backed internet trolls have reportedly critiqued U.S. targets in the past, notably including now-White House Communications Director Jen Psaki during a past stint at the State Department. Adrian Chen, a staff writer for The New Yorker who’s reported on Russian internet propaganda in the past, wrote in July that some Twitter accounts linked to Russian trolls had begun to promote Donald Trump.

And after reports that Kremlin-backed hackers were behind hacks on the Democratic National Committee’s networks and subsequent embarrassing leaks, security experts expressed concern that the Russian government could be attempting to influence the U.S. election.

“Election officials at every level of government should take this lesson to heart: Our electoral process could be a target for reckless foreign governments and terrorist groups,” warned members of the Aspen Institute Homeland Security Group, including former top Department of Homeland Security officials, in a July statement. “The voting process is critical to our democracy and must be proof against such attacks or the threat of such attacks.”