A daylong demonstration against U.S. policy in the Persian Gulf culminated yesterday in the arrest of 50 people who held a sit-in near the Vietnam Veterans and Lincoln memorials.

Sponsored by the Washington Area Coalition to Stop U.S. Intervention in the Middle East, the protest drew about 1,500 people to the site, on the Mall and just south of Constitution Avenue NW. Similar protests were held across the nation, including one in Chicago that drew several thousand people.

On Henry Bacon Drive in the District, the protesters threw down about two dozen white "body bags," each intended to symbolize a war casualty. About 500 people blocked the street until the U.S. Park Police, the agency that has jurisdiction on the Mall, began to move in. Those who had agreed to take part in the civil disobedience remained and were arrested, organizers said.

Park Police revoked a demonstration permit because of the sit-in and because the demonstrators' sound system exceeded amplification limits. The 50 people arrested -- among them anti-war activist Daniel J. Ellsberg -- were removed by officers, who emptied the contents from their pockets, photographed them and placed them in a waiting bus.

Charges included protesting without a permit, blocking the roadway and exceeding the sound amplification levels allowed at the two memorials, police said.

Organizers said about 3,000 people joined an afternoon rally at Lafayette Square, the 16th consecutive week that the coalition has demonstrated against what it calls "the drive toward war in the Persion Gulf." Scott Galindez, a spokesman for the coalition, said support for the group has grown. Recently, a drive at area universities drew 500 students, and a teach-in in Baltimore about 300 more. Many of those agreed to take part in the civil disobedience, and some were arrested for the first time, Galindez said.

The coalition is calling for the "unconditional, immediate and complete withdrawal" of U.S. forces in the gulf, an end to the naval blockade of Iraq and the withdrawal of Iraq from Kuwait. Galindez said recent developments are signs that the coalition is being heard. The vigils in front of the White House will continue, and a march on Washington will be held Jan. 26, he said.