The giant tourist signs as you enter this historic North Italian city read: “Welcome to Vicenza, City of Palladio, listed by Unesco.” Underneath in the same distinctive brown lettering is an addition: “And sold by our politicians to the US Army.” It was put there by local residents campaigning against the expansion of the nearby US military base.

Today the protesters will hold a mass meeting hoping to match or even exceed the turn-out in February, after the Italian centre-left Government of Romano Prodi had agreed to allow the new base. Then an estimated 70,000 people – more than half the population – staged a peaceful march to demand that it be stopped.

The US is to transfer more than 2,000 troops from Ramstein, Germany, to Vicenza, where there are about 3,000 troops from the 173rd airborne brigade at Camp Ederle. The US says that this will create a “Brigade Combat Team” for rapid deployment to meet threats to Western security.

Mr Prodi gave the go-ahead to the plan – initially approved by the previous centre-right Government of Silvio Berlusconi.

Many in Vicenza, however, argue that the expanded base will overwhelm a city of “unique artistic and cultural value”, famous for the buildings of the great 16th-century architect Andrea Palladio. It was declared a world heritage site by Unesco in 1994.

The new base is to be built on the little-used Dal Molin civilian airport, less than two kilometres from Palladio masterpieces such as the Teatro Olimpico, the oldest indoor theatre in Europe, and the Basilica on Piazza dei Signori, Vicenza’s central square. Last month campaigners took over the Basilica – not a church but a colonnaded civic building – for 24 hours as a “symbolic protest”. They now face charges of “illegal occupation”.

“We are not anti-American,” insists Enzo Ciscato, a Vicenza businessman who is one of the campaign organisers. “My wife is American. But we are antiwar and we want to preserve Vicenza’s heritage and character. At one time Vicenza was famous for having the highest concentration of priests and monks in Italy. Now it has the highest concentration of lapdance clubs.”

Mr Ciscato said that with Dal Molin and Camp Ederle, the US would control three million square metres of Vicenza’s land, “when local industry has just over two million square metres”. The protesters’ next target is President Bush, who is to visit Italy on June 9.

“We will be there with our banners,” said Cinzia Bottene, a protest leader, at the campaign headquarters, a large tent festooned with peace banners at the edge of the airfield. “We hope the US will realise the atmosphere is not hospitable and that it is not wanted.”

Not all residents agree: one woman who runs a shop and café near the planned base said that it would create jobs for local people and generate new business. Enrico Hullweck, the Forza Italia Mayor of Vicenza, has backed the project but has asked for government funds to help to pay for infrastructure and energy supplies and has expressed concern about the loss of a civilian airfield.

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