The Summit of the Americas has gone into overtime, as delegations from 34 countries seek common ground on such controversial issues as free trade, and the best way to combat poverty.

Hours after the schedule called for closing ceremonies, the delegations were still meeting behind closed doors.

They are trying to bridge a deep gap over proposed negotiations on a hemispheric free trade zone. Twenty-nine of the 34 countries attending the summit support the idea, but some of the biggest nations in South America do not. They include Brazil, Venezuela and Argentina.

President Bush has been pushing the concept of a free trade zone from Alaska to the southern tip of Argentina. He attended the first three hours of extended talks here Saturday in Mar del Plata, and then left for a scheduled visit to Brazil, leaving Tom Shannon, the Assistant Secretary of State for Western Hemispheric Affairs to represent the United States.

The summit was marred Friday by violent protests that resulted in serious property damage and dozens of arrests. However, when the delegates began their lengthy closing session, the city was calm, and clean-up efforts were well underway.