Venice mayor has said that the severe flooding affecting much of the Italian city is a direct result of climate change.

Mayor Luigi Brugnaro tweeted that the highest water levels in the region in more than 50 years will leave “a permanent mark”.

“Now the government must listen,” he added.

“These are the effects of climate change… the costs will be high.”

According to the tide monitoring centre, the waters in Venice peaked at 6ft. Only once since official records began in 1923 has the tide been higher, reaching 6.4ft in 1966.

The city’s St Mark’s Square – one of the lowest parts of the city – was one of the worst hit areas.

St Mark’s Basilica was flooded for the sixth time in 1,200 years, according to church records.

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Mayor Brugnaro said the famous landmark had suffered “grave damage”. The crypt was completely flooded and there are fears of structural damage to the basilica’s columns.

Pierpaolo Campostrini, a member of St Mark’s council, said four of those floods had now occurred within the past 20 years.

The city of Venice is made up of more than 100 islands inside a lagoon off the north-east coast of Italy.

Two people died on the island of Pellestrina, a thin strip of land that separates the lagoon from the Adriatic Sea. A man was electrocuted as he tried to start a pump in his home and a second person was found dead elsewhere.

Mayor Brugnaro said the damage was “huge” and that he would declare a state of disaster, warning that a project to help prevent the Venetian lagoon suffering devastating floods “must be finished soon”.