HAVANA - Cuban President Raul Castro challenged Latin American and Caribbean leaders to improve healthcare and education, telling a regional summit on Tuesday they have the natural resources to eradicate poverty but may lack the political will.

The speech also listed a series of Latin American grievances that directly or indirectly involve the United States, attempting to unify the 33 countries at the summit against their neighbor to the north, which was not invited.

"We have every possibility to abolish illiteracy," Castro told leaders of the Community of Latin American and Caribbean States (CELAC). "We should have the political will to do it."

While Castro advised fellow leaders on how to manage their economies, Cuban dissidents and the United States admonished the Cubans for stifling a protest planned outside the summit.

Cuban dissidents were expected to raise issues of human rights at an ad hoc democracy forum at a park in central Havana, but were apparently thwarted after complaining that Cuban authorities detained at least 40 activists in recent days as a part of a campaign of harassment before the summit.

With dissidents blocked from leaving their homes, only a smattering of state security agents were present where the forum was to have taken place.

"Critical voices are silenced during the CELAC summit: arrests, threats, mobiles cut," tweeted dissident blogger Yoani Sanchez.

Amnesty International criticized Cuba on Monday for its "campaign of repression against opponents and dissidents" and demanded they be allowed to demonstrate during the summit.

The US State Department on Tuesday condemned reports of harassment and arrests of activists.

"Our message to world leaders visiting: meet with everyday Cubans and independent civil society to learn what's really happening and support democratic change," Samantha Power, the US ambassador to the United States, said on Twitter.

NO GRINGOS ALLOWED

CELAC excludes the United States and Canada, both members of traditional forums such as the Organization of American States and the Summit of the Americas, which tend to be dominated by Washington.

Castro took a swipe at the United States by listing complaints such as US spying, the expansion of NATO's mission following the end of the Soviet Union, the status of Puerto Rico, and Ecuador's ongoing legal battle for compensation from US oil major Chevron Corp for environmental damage.

"We should exercise sovereignty over our natural resources and establish adequate policies relating to foreign investment and with transnational companies that operate in our countries," Castro said.

The speech by the leader of the only communist state in the hemisphere reminded neighbors of what Cuba considers two of its greatest achievements since its 1959 revolution, free healthcare and education.

Cuba often cites healthcare and education as human rights, while critics of the country's government point to the island's one-party rule and restrictions on free speech.

Castro, who succeeded his ailing older brother, Fidel Castro, as president in 2008, held a moment of silence for former Venezuelan President Hugo Chavez, whose oil subsidies for Cuba have helped sustain the economy. This is the first regional summit since Chavez died of cancer last March at age 58.

Chavez's successor, Nicolas Maduro, joined Raul Castro and other leaders in a Monday night march honoring the 161st anniversary of the birth of Cuban national hero Jose Marti.

Several leaders including UN Secretary-General Ban Ki-moon, Brazilian President Dilma Rousseff and Argentine President Cristina Fernandez have held private sessions with Fidel Castro, 87. State media photos of some of the meetings showed a smiling Fidel Castro seated and wearing a track suit, which he has preferred over military fatigues since undergoing intestinal surgery in 2006.

Rousseff told reporters she found Castro lucid with an excellent memory, relating stories about former Soviet leader Nikita Krushchev and US President John F. Kennedy.

In response to questions about Cuban dissidents, Ban's spokesman Martin Nesirky told reporters by telephone from Cuba the secretary-general has "consistently raised the question of human rights with the senior leaders that he has met."

When it was Ban's turn to speak at the summit, he avoided any direct reference to Cuba's rights record, saying only that he encouraged all leaders from the region to strengthen and uphold human rights.