Protesters Rally in Seoul Ahead of G-20 Summit

SEOUL, South Korea — Tens of thousands of protesters held a peaceful, almost festive, rally in Seoul, South Korea, on Sunday to protest the Group of 20 summit meeting that begins here on Thursday.

Organizers said that 40,000 union members, social activists and students turned out for the rally, but police officials put the number at half that, the local news media reported.

The main gathering broke up just after nightfall, although a few thousand union members stayed behind for a candlelight sit-in and a stare-down with the police, thousands of whom were present in armored riot gear. A temporary security law put in place just for the summit meeting prohibits marches after sunset, and the police used pepper spray to disperse some of the demonstrators.

“This happens every time, it’s stupid,” Kim Bo-ran, 26, said about the heavy security. “We’re peaceful. And look at the police, they all have new uniforms and new batons.”

The South Korean government is taking no chances with security during the meeting, which brings to Seoul 25 heads of state along with various billionaire business executives and representatives of organizations like the World Bank and the International Monetary Fund.

The previous G-20 meeting, in Toronto in June, was marred by the presence of rampaging black-suited protesters who smashed store windows and burned police cruisers. About 900 people were arrested.

The police in Seoul said last week that 45,000 officers were being mobilized and that military units also had been placed on high alert.

The Korean Confederation of Trade Unions, which has over 600,000 members, organized the rally on Sunday.

Many demonstrators arrived at the rally in well-organized teams, most of them led by flag bearers. The union groups wore coordinated outfits: baby-blue windbreakers or purple scarves, gray fleece jackets or olive-drab fishermen’s vests.

They sat on the damp grass on foil-wrapped squares of heavy cardboard. They sang. They chanted. They fist-pumped. And they cheered the speakers who railed against a pending South Korean free trade agreement with the United States.

One poignant focus of the gathering was a commemoration of the 40th anniversary of the death of Jeon Tae-il, a garment worker who committed suicide by self-immolation on Nov. 13, 1970.

Mr. Jeon, 22, was protesting sweatshop conditions at textile factories in Seoul and the government’s failure to enforce laws governing workplace conditions. His death helped galvanize the labor movement in South Korea, and a statue of him now stands outside the Peace Market area, where he once worked.