The FBI alerted the Democratic National Committee as recently as New Year’s Eve that hackers were once again trying to break into their computer systems, BuzzFeed News has learned.

“There was activity the day after the president issued sanctions [against Russia], looking for ways to get into the servers,” one high-level source familiar with the investigation said.

A US intelligence officer, who requested anonymity as they were not cleared to speak to the press, said that there have been “multiple attempts” to hack into the DNC since the Nov. 8 elections.

“Many of these attempts are not serious… hackers are trying to re-enter the DNC system but as far as we understand their attempts have not been successful,” said the intelligence officer, who had been in contact with the DNC over the attempts.