Executives from Facebook, Twitter and Google testified at a Senate hearing on Russian disinformation last November. (Jacquelyn Martin/AP)

Google announced Thursday that it deleted 58 accounts with ties to Iran on its video platform YouTube and its other sites, the latest sign that foreign agents from around the world increasingly seek to spread disinformation on a broad array of popular websites.

The new removals targeted 39 channels on YouTube, which had more than 13,000 views in the United States, as well as 13 accounts on the social networking site Google Plus and six accounts on Blogger, its blogging platform, the company said. Kent Walker, Google’s senior vice president of global affairs, said in a blog post that each of the accounts had ties to the Islamic Republic of Iran Broadcasting, or IRIB, which is tied to Iran’s ayatollah, and that they “disguised their connection to this effort.”

Google’s announcement comes days after Facebook suspended hundreds of accounts on its site and photo-sharing app, Instagram, that originated in Iran as well as Russia, and Twitter made a similar move. At the time, YouTube confirmed it had removed one account, called Liberty Front Press, which appeared to have connections to Iranian state media.

Google also revealed Thursday it took down 42 additional channels on YouTube that had ties to the Russian government’s online troll army, called the Internet Research Agency, since the company testified to Congress in November.

Facebook had acted on a tip from the cybersecurity firm FireEye, which later shared its findings with Google and Twitter. In response, Google briefed law enforcement officials as well as congressional investigators about its findings on Thursday, the company said.

The revelations of further coordinated inauthentic activity online are likely to grab the attention of lawmakers. The Senate Intelligence Committee plans to question top executives from Facebook, Google and Twitter next month on their efforts to protect their platforms from disinformation and other digital ills.

On Thursday, the Republican chairman of the panel, Sen. Richard Burr, said he had rejected an offer by Google to send Walker to testify. “I told them I wasn’t accepting the senior vice president,” Burr said.

Earlier this week, Microsoft announced it had found evidence of a Russia-backed effort to spoof key websites, including those for conservative think tanks, in an apparent bid to hack into visitors to those pages. In its blog post, Google said it recently took similar actions to block “attempts by state-sponsored actors in various countries to target political campaigns, journalists, activists, and academics located around the world.” Google said it most recently notified Gmail users who received suspicious emails “from a wide range of countries” on Monday.