U.S. President Barack Obama, attending a two-day regional summit in Cartagena, Colombia, said Saturday Washington wants deeper economic relations in the western hemisphere, but that existing barriers hamper greater integration.

More than 30 heads of state and government are taking part in the sixth Summit of the Americas hosted by Colombian President Juan Manuel Santos.

Mr. Obama spoke of impressive economic growth in Latin America and highlighted two U.S. free trade agreements — one with the host country, Colombia, and the other with Panama. But he also said “stark inequalities” endure in the region, with “far too many” people still living in poverty.

Speaking at the opening ceremony, President Santos urged his fellow leaders to be “partners for prosperity,” which is part of the official theme of the gathering. But other more contentious issues — including disagreements over Cuba and the failing war on drug trafficking — are likely to dominate the discussions.

The United States is facing growing discontent over its continuing opposition to including Cuba in regional partnerships. Ecuador's President Rafael Correa is boycotting the summit to protest Cuba's absence, while other leaders have said this should be the last regional meeting to exclude the communist-run island.

Another divisive issue is drug legalization, which Colombian President Santos and other leaders say should be considered as a more effective and less expensive alternative to the U.S.-led war on drugs. President Obama reiterated his opposition to the move, though he recognized the “brutal” toll of drug violence and said he is open to “legitimate discussions.”

The United States is also in the minority at the Cartagena summit in opposing Argentina's claim to the British-controlled Falkland islands.

Washington's influence in Latin America has waned since the last summit in 2009, as the region increases its economic and diplomatic ties with emerging economies such as China and India.

Haitian President Michel Joseph Martelly and his Venezuelan counterpart, Hugo Chavez, are not attending the Cartagena summit for medical reasons. Venezuela's foreign minister said Saturday that Mr. Chavez, who is battling cancer, was scheduled to travel to Cuba to continue radiation treatment.