The European Parliament was hit by cyber criminals in attacks which could be related to strikes on the European Commission (EC) last week.
Parliament employees were told to change their login information for the body's network, just as EC workers were asked to.
Remote access was also temporarily suspended, with workers requested to change passwords for connecting in this way and to take "common sense measures."
A spokesperson from the European Parliament told IT PRO employees were informed attacks had concluded but they needed to remain vigilant.
"We have to carry on with caution and obviously the powers that be are taking this very seriously," the spokesperson said.
"We were notified at the Parliament there was one [cyber attack] taking place against us. If the Commission also had one it could have been a joint thing, it could have been a separate thing."
The EC confirmed it was hit last week ahead of a significant summit in Brussels. The External Action Service, which effectively acts as the EU's foreign ministry, was also hit.
An EC spokesperson said the attacks, which led to workers' email being temporarily shut down, had not caused any major impact on operations, despite reports to the contrary.
