Iran is unlikely to go to war with the United States, former Cuban leader Fidel Castro said Friday.

"I'm sure that Iran will not perform thoughtless actions that could lead to war," Castro said in a newly-published article carried by Cuba's official media.

Castro made the remarks just two days after he met with visiting Iranian President Mahmoud Ahmadinejad who was on the third leg of a Latin American tour.

"I saw the Iranian president, he is absolutely calm and quiet, completely indifferent to the Yankee's threats, and confident about the ability of his people to confront any aggression," Castro said said.

Castro, 85, also accused the United States, Israel and their European allies of being involved in the "selective" murders of Iranian nuclear scientists.

The current tensions over Iran "threaten the very existence" of humanity, he added.

Global security was in danger not only due to a potential conflict between the US and Iran, but because of the complex situation in the Middle East and Central Asia, "where there are serious problems provoked by the contradictory and absurd imperial policy of the United States," he said.

Castro last met Ahmadinejad on the sidelines of a Non-Aligned Movement summit in Havana in 2006.