More than 40 heads of state and government and leaders from countries including North Korea are due to debate a document that backs Iran's right to nuclear technology and another sharply critical of Israel's recent war in Lebanon.

That stance could displease other summit countries such as India, Pakistan and the Philippines who have forged closer relationships with the U.S. since the Sept. 11 attacks.

Castro's health has loomed over a meeting that offers the Communist state, called an "outpost of tyranny" by Washington, a rare chance in the post-Cold War period to project itself on an international stage after more than 40 years of U.S. sanctions.

"His health is improving continuously and his convalescence is satisfactory ... but the doctors have insisted that he continue resting, and thus he will not lead the Cuban delegation at the summit," Foreign Minister Felipe Perez Roque told the summit.

The 80-year-old ceded power temporarily to his brother Raul Castro on July 31 after emergency surgery for intestinal bleeding and has not appeared in public since, though state television showed him on Thursday greeting friend and ally Hugo Chavez, president of Venezuela.

Raul Castro chaired the summit on Friday in a rare appearance for one of Cuba's most powerful figures known for shunning the limelight.

Iranian President Mahmoud Ahmadinejad used his speech to praise Cuba's role in promoting the values of the Non-Aligned Movement, first set up during the Cold War by countries who wanted to mark their independence from Washington and Moscow.

Cuba had played an "outstanding role ... in advancing the objectives of our movement, the liberation struggle and the fight against imperialism," he said.

"There is a need to strengthen or revitalize our movement more than ever," he said in a speech that contained no direct reference to Tehran's stand-off with the West over its nuclear policy.

In a colorful speech Chavez quoted poetry and joked with Raul Castro, calling Fidel: "an example of resistance and dignity against the constant aggression from the north".

Washington slammed Cuba's acting president on Friday and called for a referendum in Cuba on a transition to democracy.

"Virtually the entire hemisphere stands ready to welcome a democratic Cuba back into the inter-American fold," U.S. Commerce Secretary Carlos Gutierrez, a Cuban American, said in his speech at a Latin American economic conference in Miami.

Venezuela was also using the non-aligned summit to lobby for votes to win a seat on the United National Security Council in the face of U.S. opposition.

"The Arab League says yes, the U.S. says no, almost all of Africa says yes, the U.S. says no, Russia says yes, the U.S. says no, China says yes, now that's already a big victory, let's just wait for the results Chavez said late on Thursday.

"It won't be easy I insist, because there is a big manoeuvre going on, but Venezuela has a moral victory." he added.

South African President Thabo Mbeki also used his speech to press for reform of the U.N. Security Council.

"The people of the south ... have expressed strong support for a United Nations reform process whose outcome would be a stronger and more effective and more representative United Nations," Mbeki said.

The nonaligned movement now includes 116 nations and a wide range of agendas.

Indian Prime Minister Manmohan Singh and Pakistani President Pervez Musharraf were due to hold talks in Havana on Saturday, hoping to ease tensions after a year of recriminations over terror attacks and Kashmir.

/Reuters/