Two Romanian nationals have been arrested and charged with hacking into computer systems which controlled surveillance cameras for the Metropolitan Police Department in the US capital earlier this year, officials said Thursday.

A criminal complaint unsealed in Washington said the two -- Mihai Alexandru Isvanca, 25, and Eveline Cismaru, 28 -- were arrested in Bucharest on December 15 and charged with conspiracy and various forms of computer fraud.

The Justice Department said the pair managed to disable 123 of the police department's 187 outdoor surveillance cameras in early January by infecting computer systems with ransomware -- an effort "to extort money" in exchange for unlocking the computer, according to an affidavit filed in court.

The case "was of the highest priority" because it impacted efforts to plan security ahead of the 2017 presidential inauguration, according to officials.

The Secret Service and other agencies "quickly ensured that the surveillance camera system was secure and operational" and the investigation found no security threats as a result of the scheme.

Isvanca remains in custody in Romania and Cismaru is on house arrest there pending further legal proceedings, the Justice Department said.