The website of Gazprom Neft, the oil arm of Russian state gas giant Gazprom, went down on Wednesday after an apparent hack, in what looked like the latest attack on government-linked sites following Russia's actions in Ukraine.

The website briefly showed a statement purporting to be from Gazprom chief executive Alexei Miller, a close ally of President Vladimir Putin.

Miller last month urged the gas giant's 500,000 employees to rally around Putin to preserve Russia as a great power in the face of foreign hostility.

The statement attributed to him on what looked like a hacked version of the site cited him as making critical comments about Russia's decision to send tens of thousands of troops into neighboring Ukraine, where thousands of soldiers and civilians have been killed.

The website stopped working soon afterwards.

"The information published on the site on the morning of April 6 ... is not true and cannot be regarded as an official statement of the company's representatives or shareholders," Gazprom Neft said.

A Gazprom spokesperson dismissed the statement on the website as nonsense.

The website of the state news agency TASS was hacked in February to show a message calling for Moscow to halt what it calls its "special operation" in Ukraine.