The federal government on Friday told election officials in 21 states that hackers targeted their systems before last year’s presidential election.

The notification came roughly a year after U.S. Department of Homeland Security officials first said states were targeted by hacking efforts possibly connected to Russia. The states that told The Associated Press they had been targeted included some key political battlegrounds, such as Florida, Ohio, Pennsylvania, Virginia and Wisconsin.

The AP contacted every state election office to determine which ones had been informed that their election systems had been targeted. The others confirming were Alabama, Alaska, Arizona, California, Colorado, Connecticut, Delaware, Illinois, Iowa, Maryland, Minnesota, North Dakota, Oklahoma, Oregon, Texas and Washington.

Being targeted does not mean that sensitive voter data was manipulated or results were changed. A hacker targeting a system without getting inside is similar to a burglar circling a house checking for unlocked doors and windows.

Even so, the widespread nature of the attempts and the yearlong lag time in notification from Homeland Security raised concerns among some election officials and lawmakers.

For many states, the Friday calls were the first official confirmation of whether their states were on the list — even though state election officials across the country have been calling for months for the federal government to share information about any hacks, as have members of Congress.

“It is completely unacceptable that it has taken DHS over a year to inform our office of Russian scanning of our systems, despite our repeated requests for information,” California Secretary of State Alex Padilla, a Democrat, said in a statement. “The practice of withholding critical information from elections officials is a detriment to the security of our elections and our democracy.”