ROME, May 22 (Xinhua) -- In the latest move to keep Venice looking smart, administrators are preparing to crack down on the street artists that flock to the lagoon city hoping to earn a few euros from well-heeled tourists, Italian ANSA news agency reported Tuesday.

The council is targeting in particular the musicians who play in front of open-air restaurants and the mime artists who dress in18th century costumes and offer themselves to tourists as props for souvenir photos.

New rules soon to be approved will place a limit on the number of such "performers" in the city and ban them from St Mark's Square, the famous piazza next to the Doge's palace at the end of the Grand Canal.

The crackdown is part of a wider drive to ensure that Venice stays clean and maintains its charm despite the presence of 20 million visitors a year.

"We are fighting an increasingly intensive battle to make sure that certain standards of behavior are respected by everyone, tourists and natives," said Augusto Salvadori, a councillor in charge of "decorum."

Earlier this month, the city council said it will deploy stewards to stop tourists going about bare-chested, lounging around in doorways and eating sandwiches in St Mark's Square.

The city is also working on laws to stop the sale of fast food in the piazza so as to limit the amount of rubbish that accumulates there and which street cleaners can only remove once a day.

Even the vendors who sell tourists grain to feed the pigeons in St Mark's Square are being forced to move away so as to reduce the quantity of droppings which soil the piazza and erode its buildings.

"People who violate these norms protecting the city should be punished with hefty fines," Salvadori said.

Venice has been looking for many years for ways to finance the extra cleaning and maintenance work.

The idea of a "tourist tax" to save Venice -- of as much as 50 euros per visitor -- has frequently been raised but the mayor says such a levy would be impossible to enforce.

Recently the council said the addition of a few extra euros to the price of hotel accommodation and souvenirs would be a better solution.