Former Cuban leader Fidel Castro warned Monday that "a U.S.-Israeli attack on Iran would inevitably unleash a bloody war."

"Because of its ability to fight, the number of inhabitants and the size of the country, an attack on Iran is not like the previous Israeli military adventures in Iraq and Syria," Castro wrote in an article.

"A bloody war would inevitably start. There should be no doubt about it," the 85-year-old former leader added, speculating that Israel intends to attack Iran as it did when targeting the nuclear facilities in Syria in 2007 and in Iraq in 1981.

Castro also cited U.S. Ambassador to the UN Susan Rice as saying that an attack on Iran is a real growing option and that the U.S. government is considering putting an end to the current Iranian leadership to prevent it from creating a nuclear arsenal.

Western countries are ratcheting up pressure on Iran after a report by the international nuclear watchdog IAEA said the country's nuclear program had an agenda to develop weapons.

Tehran has completely rejected the report, calling it "unbalanced, unprofessional and politically-motivated."