Facebook, Twitter, Microsoft and other leading tech companies met Friday to talk about protecting their platforms from manipulation during the midterm elections.

The plans, first reported by BuzzFeed, were confirmed to CNNMoney by a person familiar with the meeting. Google was among the other companies that were invited.

The companies, especially Facebook and Twitter (TWTR), have been criticized for how their platforms were used to spread misinformation during the 2016 presidential election, particularly by Russian entities.

Executives of those two companies are expected to testify before the Senate Intelligence Committee next month to answer questions about their roles protecting elections from misinformation.

The companies have promised that they are working to protect their businesses from improper efforts to influence US voters.

Earlier this week, Facebook (FB) said it had taken down 652 pages, accounts and groups that it identified as part of coordinated disinformation campaigns that had ties to foreign countries, including Iran and Russia.

And Microsoft (MSFT) this week announced what it called a "Defending Democracy program" to offer protections to candidates and related organizations.

BuzzFeed reported that Facebook's head of cybersecurity policy, Nathaniel Gleicher, invited employees from a dozen companies to the meeting, at Twitter's headquarters in downtown San Francisco.

Nine of the companies met at Facebook headquarters in May, with officials from the Department of Homeland Security and the FBI, BuzzFeed reported.

Twitter declined comment. Spokespeople for Facebook, Google (GOOG) and Microsoft did not immediately respond to requests for comment on the meeting.

Separately Friday, the Department of Homeland Security and FBI held a briefing with election officials and Facebook and Microsoft to discuss actions taken by both companies "to combat foreign threats," a DHS statement said.

It was the second call in recent weeks DHS has hosted with Facebook on measures to combat "malicious interference operations," the statement said.