Earlier in the day, the German Chancellor's spokesperson Steffen Seibert told reporters that government websites had been inaccessible since 10:00 a.m. local time (09:00 GMT) due to an attack caused by a number of external systems.
"CyberBerkut has blocked the German Chancellor and the Bundestag's websites," a statement published on the organization's website read.
"That's why we appeal to all the people and the government of Germany to stop their financial and political support of the criminal regime in Kiev, which unleashed a bloody civil war," the statement read.
The cyberattack coincides with an official visit by Ukrainian Prime Minister Arseniy Yatsenyuk to Berlin, scheduled for Wednesday and Thursday.
CyberBerkut repeatedly targeted the websites of the Ukrainian government throughout 2014 as a reaction to the ongoing armed conflict and the severe humanitarian crisis caused by Kiev's military operation which was launched against independence supporters in Donetsk and Luhansk regions in mid-April.