Sen. Mark Warner, the top Democrat on the Senate Intelligence Committee, complained that it is "unacceptable" that the Homeland Security Department waited until Friday to notify individual states that Russian hackers attempted to breach their election systems.

"It's unacceptable that it took almost a year after the election to notify states that their elections systems were targeted, but I'm relieved that DHS has acted upon our numerous requests and is finally informing the top elections officials in all 21 affected states that Russian hackers tried to breach their systems in the run up to the 2016 election," the Virginia Democrat said in a statement Friday evening.

About an hour earlier, top state officials began putting out statements that DHS had reached out to tell them that they were targeted by Russian hackers during the 2016 election.

Though a DHS official testified before the Senate intelligence panel in June that 21 states had been attacked, the agency refused to reveal which ones had been targeted.

So far officials from Alabama, Colorado, Illinois, Maryland, Minnesota, Virginia, Washington, and Wisconsin have come forward about being contacted by DHS. In some cases, the states had no idea that hacking attempts had been made. A report from the Associated Press said that in most cases the breaches were not successful, but didn't specify which ones were a success.

"We have to do better in the future. Our elections are the bedrock of our democracy, and DHS needs to notify states and localities in real-time when their systems are targeted," Warner said. "While I understand that DHS detects thousands of attempted cyber attacks daily, I expect the top election officials of each state to be made aware of all such attempted intrusions, successful or not, so that they can strengthen their defenses -- just as any homeowner would expect the alarm company to inform them of all break-in attempts, even if the burglar doesn't actually get inside the house."

Warner took the opportunity to promote an intelligence authorization bill for fiscal 2018 that he said addresses the targeting of election systems and would force DHS to provide "timely and specific threat information" to state officials.

"All 50 states need to be proactively strengthening the security of their election systems in the face of this threat," Warner said. "The Senate Select Committee on Intelligence will continue our bipartisan investigation into what happened in 2016, and we will continue to determine what steps we need to take to stop the next attack on our democracy."