WASHINGTON, DC (CBSNewYork/AP) – Social media executives headed to Capitol Hill Wednesday to face more questions about how they’re working to combat foreign meddling with midterm elections just months away.

Twitter’s CEO Jack Dorsey and Facebook’s number two executive, Sheryl Sandberg, spoke before the senate intelligence committee. Sandberg admitted that Facebook was too slow to act after Russia allegedly used the social media platform to influence the 2016 presidential election.

“We are more determined than our opponents and we will keep fighting,” Sandberg said. She called the fight to protect American democracy an “arms race,” as Facebook CEO Mark Zuckerberg has in the past.

Notably absent from the hearing was Google, which one lawmaker said was an “arrogant” move on the company’s part. Sen. Marco Rubio said he’s sure that Google executives “don’t want to be here to answer these questions.”

The Justice Department says it’s convening a meeting later this month to discuss concerns that social media companies may be hurting competition and “intentionally stifling the free exchange of ideas on their platforms.”

Some Republicans, including President Trump, have pushed the idea that Twitter is “shadow banning” some in the GOP because of the ways search results have appeared. Twitter denies that’s happening.

(© Copyright 2018 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)