Retired Cuban leader sternly cautions North Korea and US of dangers of nuclear war in first column in nearly nine months

Retired Cuban leader Fidel Castro published his first column in nearly nine months on Friday, urging both friends and foes to use restraint amid tensions on the Korean Peninsula.

In the brief piece published in Communist Party daily Granma and other official media, Castro warned of the impact that nuclear war could unleash in Asia and beyond. He said Havana has always been and will continue to be an ally to North Korea, but gently admonished it to consider the well-being of humankind.

"Now that you have demonstrated your technical and scientific advances, we remind you of your duty to the countries that have been your great friends, and it would not be fair to forget that such a war would affect ... more than 70% of the planet's population," he said.

Castro used stronger language in addressing Washington, saying that if fighting breaks out, President Barack Obama's government "would be buried by a flood of images that would present him as the most sinister figure in US history. The duty to avoid (war) also belongs to him and the people of the United States."

North Korea has issued a series of escalating threats in recent weeks as the United States and South Korea have conducted joint military exercises beginning in March, and expressed anger over U.N. sanctions imposed after it held a nuclear test in February. Pyongyang says it needs nuclear weapons for self-defense, and on Tuesday it announced it would restart a plutonium reactor that was shut down in 2007.

Analysts say the elevated rhetoric is probably calculated to push for concessions from South Korea, prod Washington into talks and bolster the image of North Korean leader Kim Jong Un.

But Castro called the situation "incredible and absurd," and said war would cause terrible harm to the people of both Koreas and benefit no one.

"This is one of the gravest risks of nuclear war since the October Crisis in 1962 involving Cuba, 50 years ago," he wrote, a reference to what is known in English as the Cuban Missile Crisis.

Castro last published one of his columns known as "Reflections" on June 19, 2012. In October, amid the latest round of rumors of his purportedly dire health, he said he had stopped writing them not due to illness but because they were occupying space in official newspapers and state TV news broadcasts that was needed for other uses.

Letters signed by him have been released periodically, however, including a message of condolences last month following the death of Venezuelan President Hugo Chavez, a close friend and ally.

He also appeared in person in February at a voting station, bantering for more than an hour with poll workers, island reporters and children.

Castro has been out of office since 2006, when a near-fatal intestinal ailment forced him to hand power to his younger brother Raul.