Fidel Castro addressed Cuba's parliament in his first public government act in four years, and appealed to world leaders, including US President Barack Obama, to avoid a nuclear war.

The return of the 83-year-old to the National Assembly, transmitted live by Cuban state television, crowned a spate of recent public appearances after a long period of seclusion due to illness.

It was his first participation in a public government meeting since 2006, when intestinal surgery forced a lengthy absence.

In 2008, he formally handed over the presidency of the Caribbean country to his younger brother Raul Castro.

The leader of Cuba's revolution, who retains his parliament seat and the post of First Secretary of the Communist Party, dressed in long-sleeved green military fatigues, but without rank insignias, for the session.

After being helped to walk in and being greeted by a standing ovation and shouts of ‘Viva Fidel,’ he used the meeting to expound again his recent warnings that US pressure against Iran could push the world to a nuclear conflagration.

In a 12-minute prepared speech delivered in a firm but sometimes halting voice, he urged world leaders to persuade Mr Obama not to unleash a nuclear strike against Iran.

Mr Castro said such an attack could occur if Iran resisted US and Israeli efforts to enforce international sanctions against it for its nuclear activities.

Mr Castro also referred to the case of one of five convicted Cuban spies jailed in the US, Gerardo Hernandez, saying he hoped his wife would be allowed to visit him or that he could even be released.

Following his 2006 illness, Fidel Castro disappeared from public view and was only seen occasionally in photographs and videos. But since 7 July, he has emerged from four years of seclusion and has made several public appearances.