HAVANA - Raul Castro proposed term limits for Cuban politicians on Saturday - including himself - a remarkable gesture on an island ruled for 52 years by him and his brother. The 79-year-old president lamented the lack of young leaders in government, saying the country was paying the price for errors made in the past.

Castro told delegates to a crucial Communist Party summit that he would launch a "systematic rejuvenation" of the government. He said politicians and other important officials should be restricted to two, five-year terms, including "the current president of the Council of State and his ministers" - a reference to himself.

Castro officially took over from his brother Fidel in 2008, meaning he'd be at least 86 when his second term as Cuban leader ended, depending on how the law is written.

The proposal was made in the latter stage of a two-and-a-half hour speech in which the Cuban leader forcefully backed a laundry list of economic changes to the country's socialist system, including the eventual elimination of the ration book and other subsidies, the decentralization of the economy and a new reliance on supply and demand in some sectors.

Still, he drew a line in the Caribbean sand across which the reforms must never go, telling party luminaries that he had rejected dozens of suggested reforms which would have allowed the concentration of property in private hands.

Castro said the country had ignored its problems for too long, and made clear Cuba had to make tough decisions if it wanted to survive.

"No country or person can spend more than they have," he said. "Two plus two is four. Never five, much less six or seven - as we have sometimes pretended."

Dressed in a white guayabera shirt, the Cuban leader alternated between reassurance that the economic changes were compatible with socialism, and a brutal assessment of what has not worked in the past.

Castro said the monthly ration book of basic foods, perhaps the most cherished of subsidies, represented an "unbearable burden ... and a disincentive for work."

Still, he said that in Cuba, "there will never be room for shock therapy."

Of the term limits, Castro said he and his brother had made various attempts to promote young leaders, but that they had not worked out well - perhaps a reference to the 2009 firing of Cuba's photogenic foreign minister and vice president.

"Today we face the consequences of not having a reserve of substitutes ready," Castro said.

As with the proposals on economic changes, the term-limit idea does not yet carry the force of law since the party gathering lacks the powers of parliament. But it is all but certain to be acted on quickly by the national assembly.

Fidel Castro was not present for the speech, but a chair was left empty for him near his brother.