WASHINGTON – Hackers broke into the Federal Aviation Administration’s computer system last week, accessing the names and Social Security numbers of 45,000 employees and retirees.

The agency said in a statement Monday that two of the 48 files on the breached computer server contained personal information about employees and retires who were on the FAA’s rolls as of the first week of February 2006.

The server that was accessed was not connected to the operation of the air traffic control system and there is no indication those systems have been compromised, the statement said.

“The FAA is moving quickly to prevent any similar incidents and has identified immediate steps as well as longer-term measures to further protect personal information,” the statement said. The agency said it is providing a toll-free number for employees “who believe they may be affected by the breach.”

All affected employees will receive letters notifying them of the breach, the statement said.