OPM employees in the office Thursday discovered they were unable to log on to their personal email accounts or surf social media sites. The apparent change in policy came abruptly, with no prior communication from OPM leaders, employees said.

OPM Data Breach: What You Need to Know

The new restrictions come almost a month after OPM announced a massive breach of its network, exposing personal information on millions of current and former federal employees. The new Internet policy is a direct result of actions being taken in the wake of that breach, OPM officials confirmed.

"Out of caution, and in light of the recent breaches, OPM has recently tightened restrictions on Internet access using web security technology," an OPM spokesperson said Thursday, suggesting there might be more to come.

"As we move forward with security measures which will ensure both agency and individual security, OPM will continue to monitor and make adjustments to our web security policies," the spokesperson said.

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