About 130 protesters were arrested at an Occupy Chicago demonstration early on Sunday after they erected tents and refused to leave a park next to Lake Michigan after its closing time, police said.

The breakup of the protest in Grant Park was the second mass arrest of demonstrators from Occupy Chicago in the past week. A week ago, about 175 protesters were arrested.

In Philadelphia on Sunday, 15 people were arrested when a group of protesters blocking traffic refused to move, authorities said. They face misdemeanor charges of obstructing a highway.

The Philadelphia arrests were the first there since Occupy Philadelphia began in sympathy with the Occupy Wall Street movement in New York.

In Chicago, the protesters were charged with violating a city ordinance, the equivalent of the lowest misdemeanor, and most were released after agreeing to appear in court, police said.

Grant Park, the site of large protests against the Vietnam War during the Democratic Party's convention in Chicago in 1968, is supposed to be closed after 11 pm, police said.

The protests, which launched more than a month ago in New York and focus on anger over government bailouts of big banks and persistent high unemployment, have sprung up across the United States and in other countries.

The demonstrations focus on what protesters see as unequal treatment of the 99 percent of Americans versus the top 1 percent of earners, but critics have said the groups lack clear objectives.

Hundreds of Occupy Wall Street demonstrators have been arrested in New York since the protests began. There have also been numerous arrests in Tampa, Florida, Cincinnati, Des Moines, Minneapolis, Denver and other cities.