Former US vice-president Al Gore has hit out at Rupert Murdoch's News Corporation, accusing it of "an abuse of power" by forcing his liberal TV station off air in Italy because it did not fit in with the media giant's "ideological agenda".

In an interview with the Guardian, Gore said the Current TV news and documentary channel was told unexpectedly three weeks ago that it could no longer be carried by Sky Italia because of its decision to hire a US left-leaning commentator often critical of Murdoch's company.

He added that the decision reflected how News Corporation operated worldwide. "News Corporation is an international conglomerate with an ideological agenda. It seeks political power in every nation they operate. They wield that power to shut down voices that disagree with the agenda of Rupert Murdoch," Gore said.

The decision, he added, was "a complete shock" but Current TV executives were told "off the record that the decision was taken on News Corp instructions from New York". The primary reason, he said, was "because Current is launching Keith Olbermann next month".

Olbermann – who styles himself as a leftwing alternative to the rightwing shock jock journalism of Fox News – worked at rival cable news network MSNBC until he left abruptly in January. This came after he was briefly suspended by MSNBC in November for making donations to three Democratic candidates in the midterm elections without seeking prior approval, in breach of company rules. "Olbermann has often been critical of News Corporation," Gore added.

Current TV broadcasts around the world, including the UK, but the channel has been more successful in Italy, where it claims that "one in three" Sky Italia viewers watch at some point during the week. However, Gore said that decision to not renew the channel's existing distribution deal also had implications in the UK – where News Corp's takeover of BSkyB is under review on the grounds of "media plurality".

"I know that News Corp is close to reaching an agreement to buy BSkyB. Now I may not be a party to that debate, but if anybody believes that [News Corp] will remain hands off if there are diverse opinions that do not agree with its ideological agenda then they are fools. This is proof positive of their abuse of power," Gore said.

However, Current TV's existing agreement with BSkyB does not expire until next year, so there is no immediate threat to its UK position on the satellite service in this country.

Gore also said he understood there has been "a rapprochement" in the struggle between News Corp and Silvio Berlusconi's media empire in Italy. Current TV has run several documentaries critical of the Italian premier and his government. "Sky Italia is in the midst of negotiations to enter the digital terrestrial television market and the need Berlusconi's support," he said.

Gore added that he had a "pleasant personal relationship" with Murdoch dating back to the former vice-president's time in the White House, and said that he wasn't sure exactly on whose authority the decision was made to order Current TV off the air in Italy. He said that he didn't want "to make this ad hominem" but added it was clear that Murdoch and News Corp had too much power.

Programming aired by Current TV in Italy has included Citizen Berlusconi, a documentary first produced by the US PBS network, and about the consequences of handing a media mogul formal political power.

"Anglo-American political theory highlights the problem. Too much power in the hands of one person is dangerous, no matter the ideology," Gore said. "The conversation of democracy, which used to happen in newspapers or in other public places now happens on the television screen. But this is a public space in which gatekeepers charge rents."

He cited the example of the 2003 Iraq war, in which News Corp had acted as "an aggressive cheerleader" for the US-led invasion, to the point where "three quarters of the American public got the impression that Saddam Hussein was responsible for the attacks of 2001". This journalism, Gore said, "has consequences" and he argued that "our democracy is much better when there are diverse viewpoints" to inform decision-making.

News Corp insiders said that Gore's criticisms were misplaced and that Current TV had been dropped after the two sides couldn't reach a commercial agreement.

A News Corp spokesman said: "The non-renewal of Current TV's carriage agreement with Sky Italia is purely commercial. Current TV asked Sky Italia for double the carriage fee when prime-time viewing had fallen by 40% in the past year. Sky Italia's offer was in line with the market and reflected the performance of the channel. It had nothing to do with politics."

• To contact the MediaGuardian news desk email editor@mediatheguardian.com or phone 020 3353 3857. For all other inquiries please call the main Guardian switchboard on 020 3353 2000. If you are writing a comment for publication, please mark clearly "for publication".

• To get the latest media news to your desktop or mobile, follow MediaGuardian on Twitter at http://twitter.com/#!/mediaguardian and Facebook at http://www.facebook.com/mediaguardian