HARRISBURG, Pa. — Pennsylvania’s top elections official said Monday that he thinks Russian hackers who tried unsuccessfully to penetrate the state’s election systems had hoped to alter voter registration records to sow confusion and frustration right before last year’s presidential election.

Secretary of State Pedro Cortes, however, said he otherwise has been given very little information by the U.S. Department of Homeland Security about the supposed attempts by Russian hackers, including how the hackers were connected to Russia, their method and the timing of their attempts.

The Department of Homeland Security also did not specify which Pennsylvania election system was scanned for vulnerabilities, Cortes said, but he guessed it was the state’s voter registration system. Such an attempt might have sought to alter records just before polls opened in last year’s election, said Cortes, a Democrat.

“I think it’s more of a matter of perhaps creating confusion and frustration, being able to maybe change records at the very last minute, when pollbooks already have been printed and people believe that they’re going to a certain polling place, and then they show up at that polling place but their names don’t either appear at all on the pollbooks or now they appear that you are registered across the town or across the state,” Cortes said.

Cortes said that all evidence points to the hackers’ attempts being unsuccessful. The Department of State’s cybersecurity defenses are “robust” and benefit from the state government’s larger information protection systems, he said.

A Homeland Security official first informed the Pennsylvania Department of State in a minutes-long call Friday that Pennsylvania was one of 21 states said to have been targeted by Russian hackers, Cortes said. The official seemed to read from a script and did not answer follow-up questions about the matter, he said.

Federal officials have said that, in most of the 21 states, the targeting was preparatory activity such as scanning computer systems. The targets included voter registration systems but not vote tallying software. Officials said there were some attempts to compromise networks but most were unsuccessful.

Only Illinois reported that hackers had succeeded in breaching its voter systems.

Cortes said Pennsylvania will seek more information about the matter, including why it took so long for the federal government to notify the states.

“It’s disheartening that it took this long, because it should not have been a big secret,” Cortes said.

However, should Pennsylvania learn more from the Department of Homeland Security, it may not reveal that information publicly because of security concerns, Cortes said.

In August, Pennsylvania largely denied The Associated Press’ open-records request for documentation on any attempts to hack elections systems in the state, citing exemptions related to public safety, trade secrets and attorney-client privilege, among others.

Cortes said Pennsylvania wants President Donald Trump’s administration to provide help and money to states to protect election systems.

“This is one problem that is not going to go away,” Cortes said.

Russia has denied hacking into the U.S. election, in which Trump, a Republican, won Pennsylvania and defeated Hillary Clinton, a Democrat. Trump has called reports of Russian meddling in the election a hoax.