ROME — Protests against widening income disparity took place across western Europe and Asia on Saturday as the Occupy Wall Street movement spread around the globe. Rome’s demonstration turned violent, contrasting with events elsewhere.

More than 500 marchers wielding clubs attacked police, two banks and a supermarket in Rome, Sky TG24 reported. Authorities responded with tear gas and water cannon.

In Frankfurt, 5,000 marchers gathered by the European Central Bank headquarters, firing soap bubbles from toy pistols with plans to camp out, ZDF German television said.

In London, police barred protesters from entering Paternoster Square, home to the London Stock Exchange.

In the shadow of St. Paul’s cathedral, protesters waved banners with slogans that read “No bulls, no bears, just pigs” and “Bankers are the Real Looters.”

“The financial system benefits a handful of banks at the expense of everyday people, the taxpayers,” said Spyro Van Leemnen, a 27-year-old public relations agent and a core member of the London demonstrators. “The same people who are responsible for the recession are getting away with massive bonuses. This is fundamentally unfair and undemocratic.”

The Occupy London Stock Exchange protest drew about 4,000 people, according to its organizers. Three people were arrested, including two for assaulting police officers, according to a Metropolitan Police statement.

The Occupy Wall Street rallies started last month in New York’s financial district, where people have been staying in lower Manhattan’s Zuccotti Park to protest inequality and advocate higher taxes for the wealthy. More than 700 demonstrators in New York have been arrested since the protests began, mostly on disorderly conduct charges.

The International Monetary Fund cut its forecast for global economic growth to 4 percent this year and next, compared with June forecasts of 4.3 percent in 2011 and 4.5 percent in 2012. Group of 20 finance ministers met Saturday in Paris for talks to find a solution to Europe’s debt crisis as it threatens to tip the world economy back into a recession.

In Italy, with a youth unemployment rate of 27.6 percent, protests turned violent. Thirty police were injured and protesters were trapped in San Giovanni square, Sky TG24 reported. Firecrackers were thrown at the Ministry of Defense and windows of Cassa di Risparmio di Rimini and Poste Italiane shattered, according to the report.

“I have the feeling that the worst of Europe planned to meet in Rome,” Mayor Giovanni Alemanno told Sky TG24. “Now, the citizens of Roman are those who have become angry.”

Protests in 50 German cities and Paris were peaceful. In Berlin, 6,000 took to the streets; they numbered 1,500 in Cologne, ZDF said. “A few hundred” people gathered at the Paris city hall, according to BFM TV.

Thousands marched in Madrid with placards criticizing bank bailouts.

In Zurich, about 200 protesters coalesced on Paradeplatz, playing monopoly and sipping free coffee from a stand. The protests were peaceful.

In Taiwan, organizers drew several hundred demonstrators, who mostly sat quietly outside the Taipei World Financial Center, known as Taipei 101.

Levin Jiang, 22, an English major at Taipei’s Fu Jen Catholic University, joined others marching and singing the communist anthem L’Internationale in front of the Hermes watch shop in the mall of what was until last year the world’s tallest building.

“I’m angry about the unjust capitalist society,” he said. “I’m anti-capitalism.”

In Seoul, 600 converged on the city hall after changing the location of the protest as police banned the rally Saturday, Yonhap News reported. They urged clamping down on speculative capital and demanded lower college tuition.

In Hong Kong, about 200 people gathered at the Exchange Square Podium in the city’s central shopping and business district, according to Napo Wong, an organizer.

“Hong Kong is heaven for capitalists,” said Lee Chun Wing, 29, a community college social sciences lecturer in Hong Kong. “Wealth is created by workers and so should be shared with the workers as well. Capitalism is not a just system.”

In Tokyo, where morning rain may have deterred some from joining three planned protests, more than 120 people demanding an end to nuclear power generation marched from Hibiya Park to the offices of Tokyo Electric Power Co., owner of a crippled plant that’s spewed radiation, causing the evacuation of thousands after Japan’s March 11 earthquake.