Amid the ongoing Russian invasion of Ukraine, a bipartisan group of 22 U.S. senators on Sunday asked Homeland Security Secretary Alejandro Mayorkas for a briefing on his department’s efforts to protect the U.S. from Russian cyber and disinformation threats.

“Given Russia’s history of disruptive and disinformation activities, we are concerned that the United States may be targeted in retaliation for actions taken to impose costs on Russia for its unprovoked invasion of Ukraine,” the senators wrote in their March 13 letter. “As we stand with the Ukrainian people, impose crushing sanctions on Vladimir Putin’s regime, and push for additional security assistance to help Ukraine defend itself, we also must work to secure the homeland from retaliatory cyber activities.”

U.S. intelligence officials last week told a House panel that so far they’ve observed some Russian cyber-attacks against Ukraine but not against the U.S.

As Russia was organizing and building its forces for the invasion of Ukraine, the Department of Homeland Security’s Cybersecurity and Infrastructure Security Agency (CISA) created the Shields Up website to provide guidance to all organizations to help them strengthen their cyber posture in case of any Russian cyber-attacks.

Still, the senators want more details on what CISA and DHS are doing to protect the homeland. They want to be briefed on what CISA is doing to “monitor and pro-actively defend” against Russian cyber threats and if there is a plan in place if attacks do occur. They also want to know if any U.S. entities are likely targets of Russia, how Shields Up guidance is being disseminated, how DHS is defending against Russian disinformation, and how CISA is doing operational coordination with U.S. allies and partners.

The letter was led by Sens. Jacky Rosen (D-Nev.) and Mike Rounds (R-S.D.).