"I resign. I am ashamed of the government's actions. I'm sorry," said a tweet posted from Russian Prime Minister Dmitry Medvedev’s official Russian language Twitter account on Thursday.

medvedev twitter Russian Prime Minister Dmitry Medvedev's official twitter page Photo: twitter

This was followed by a series of tweets denouncing Russian President Vladimir Putin, his policies on Crimea, and his decision to block food imports from European Union nations and the United States.

"We could return to the 1980s. That is sad. If that is the objective of my colleagues in the Kremlin, they'll achieve that quickly," a tweet said. “I'll be a freelance photographer,” another one said.

A Russian government spokesperson later told the state-run RIA Novosti news agency that Medvedev's account had been hacked and that the messages are “not genuine.”

“We're working on the problem,” an unnamed government spokesperson reportedly said. However, tweets critical of the Russian government continued to be posted from Medvedev’s account and were re-tweeted by many of his more than 2.5 million followers.

"I've wanted to say this for a long time: Vova , you're wrong!" read a tweet, using Putin’s nickname.

“Crimea isn't ours. Please retweet,” said another tweet, renouncing Moscow’s claim on the Black Sea peninsula, which was annexed by Russian forces in March.

A Russian group named Shaltay-Boltay, which is Russian for Humpty-Dumpty, claimed responsibility for the attack and said that it had also accessed photographs from Medvedev’s compromised iPhone. 

“Several mail accounts, including Gmail and the contents of three iPhones of a certain prime minister have randomly fallen into our hands on the internet. Details later,” it tweeted.

The tweets from Medvedev’s account have since been removed.