The world's most popular YouTube channel has once again attracted controversy after fans of PewDiePie defaced a World War II memorial in New York.

The Brooklyn War Memorial in Cadman Plaza Park was tagged with the graffiti, "Subscribe to PewDiePie", referencing a movement dedicated to preventing the YouTube channel from being dethroned by the Indian channel T-Series.

PewDiePie, whose real name is Felix Kjellberg, has been the most popular channel on YouTube since 2013, but faces significant competition from T-Series.

The Indian record label was expected to dethrone him in October, with a data analytics firm originally predicting the takeover would take place in October.

The title of the world's most popular YouTube channel finally changed hands last month when T-Series took over – but only for eight minutes.

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Less than 15,000 subscribers currently separate the two channels, which each boast more than 88 million subscribers.

The sustained support campaign for PewDiePie now appears to be going to desperate lengths to prevent the takeover, with the war memorial graffiti condemned by local residents.

"I don't know what pewdiepie is but based on this it is terrible," one person wrote in the Brooklyn sub-Reddit, where an image of the graffiti originally appeared.

Mr Kjellberg previously stated he is not bothered if he is overtaken by T-Series, saying in an October video: "I don't really care about T-Series, I genuinely don't."

He has since gone on to urge his fans to do whatever they can to keep his channel on top.

"I love it, please keep it up," he said. "Just don't do anything illegal, OK, because that would look bad on me. That's the only reason."

The New York war memorial incident is not the first time PewDiePie supporters have committed acts of vandalism in support of the channel.

Images of defaced walls have spread across social media in recent weeks, showing messages stating "subscribe to PewDiePie" and "Defeat T-Series".

Cyber vandals even took over a section of the Wall Street Journal website in December in order to post a message of support for PewDiePie.

Other fans have used less controversial methods to promote PewDiePie, with one fan hiring billboards in his home town to advertise the channel.

A fan meet-up in Estonia last month saw a crowd march through the streets of Tallinn waving banners encouraging people to subscribe to the YouTuber.

Billionaire entrepreneur Elon Musk also joined the campaign by hosting a popular segment on the channel called Meme Review.