Nicolas Maduro had barely gotten off his plane at the Summit of the Americas on Friday before he gave a symbolic poke in the eye to Washington, paying a visit to a monument honoring victims of the 1989 U.S. invasion of Panama.

A crowd of several hundred greeted the Venezuelan president at the memorial in the poor downtown neighborhood of El Chorrillo, which saw the heaviest fighting during the invasion. "Maduro, stick it to the Yankee!" they chanted.

Maduro said he would personally deliver to President Barack Obama a petition from Panamanian victims demanding the U.S. apologize and compensate victims of the invasion.

"Never again a U.S. invasion in Latin America," Maduro said.

He also praised Panama's former military strongman Omar Torrijos, who negotiated with Jimmy Carter the return of the American-built Panama Canal.

All eyes are on Obama and Cuba's Raul Castro at the summit, where the two leaders are expected to meet Saturday for the first time since their historic December announcement that they would move to restore diplomatic relations severed since 1961.

But other leaders were also going about their business: meeting on the sidelines among themselves and with academics, corporate CEOs, the heads of NGOs and civil society groups.

The presidents of Central America's "northern triangle" — Guatemala, El Salvador and Honduras — asked the United Nations for support for a security and development plan that also aims to reduce emigration from the violence-plagued countries toward the United States.

The three presidents delivered to U.N. Secretary-General Ban Ki-moon a document outlining their strategy, which is backed by the Washington and the Inter-American Development Bank.

They were expected to meet Friday with Obama, who has requested $1 billion in aid for Central America in his budget proposal to Congress. The leaders also planned to meet with U.S. lawmakers.

Guatemalan President Otto Perez Molina and Honduran President Juan Orlando signed an agreement to launch a border customs union that aims to ease the flow of people and goods between the two countries, something they have long aspired to create.

"We are taking important steps in the processes of integration and attracting investment with this customs union," Perez Molina said.

Bolivian President Evo Morales made time for a friendly soccer match Friday with delegates to the alternative Peoples' Summit.

A big soccer fan who is fond of kicking the ball around with different groups as part of his presidential outreach, Morales donned a white-and-green No. 10 jersey with "Evo" on the back.

The People's Summit was also the scene of a third day of confrontations between opponents and supporters of the Cuban government, prompting police to get between the two camps and close off access to the Hotel El Panama for nearly 40 minutes.

Castro supporters shouted "Mercenaries!" — an epithet commonly directed at dissidents in Cuba — as they faced off with government opponents who brandished signs such as "Democracy is respect."

At the Panama invasion monument, Trinidad Ayola, who lost her husband in the fighting, held back tears as she talked about Maduro's visit. She said it was the first time any head of state had come calling in the two decades since the monument was built, and she called on Obama to apologize for the 1989 invasion.

"Maduro is interested in the suffering of the people," she said, while "all Obama cares about is the interests of the multinationals."

Tensions between Washington and Caracas have risen in recent weeks due to financial and travel sanctions that the U.S. imposed on seven Venezuelan officials over alleged human rights abuses.

Maduro also plans another gift of sorts for Obama at the summit: petitions signed by millions of Venezuelans in recent days demanding the U.S. president rescind the sanctions.