The European Parliament website was affected by a hacking attack, spokesman Jaime Duch said on Wednesday.
Duch said the website was down due to a Distributed Denial of Service (DDoS) attack.
Parliament President Roberta Metsola said it was a "sophisticated attack" and that a pro-Kremlin group had claimed responsibility.
She noted that the attack followed the EU lawmakers' voted to name Russia a "state sponsor" of terror.
"My response is: Slava Ukraini (Glory to Ukraine)," Metsola said, DW reports.
