Retired Cuban leader Fidel Castro blamed the Ukrainian government in Kiev for the downing of a Malaysia Airlines passenger plane.
He also criticised Israel's ground offensive in the Gaza Strip, and the United States for saying Israel has a right to defend itself.
Castro's comments were made in an opinion column published by state media entitled "Extraordinary Provocation." It came days after he met with Vladimir Putin during the Russian leader's tour to boost ties with Latin American nations including Cuba, which during the Cold War was the Soviet Union's biggest ally in the hemisphere.
Castro wrote that the Malaysia Airlines plane was flying over territory "under the control of the bellicose government of the chocolate king Petro Poroshenko," using the nickname of the Ukrainian president, who leads a large confectionary business.
The plane was shot down as it flew over a conflicted part of eastern Ukraine, killing 298 people. Responsibility for the attack remains unclear.
He recalled that Cuba stood with Ukraine after its 1986 nuclear accident at the Chernobyl power plant, attending "to the health of many children," and said the island nation "cannot refrain from expressing its repudiation of the action by the same anti-Russian, anti-Ukrainian and pro-imperialist government."
He also criticised Israel's ground offensive in the Gaza Strip, which was launched Thursday, calling it a "repugnant crime," and the United States for saying Israel has a right to defend itself. US President Barack Obama, he said, "backs Goliath against David."
Castro left office provisionally in 2006 when he was stricken by a near-fatal illness. He formally left the presidency in 2008, ceding way for his younger brother Raul to take power.
He maintained a public voice by writing regular opinion columns called "Reflections" that were published across official newspapers and websites, and read out in their entirety by state TV news anchors. In 2012, he announced that he was retiring as a columnist as well, although he has continued to publish occasionally.
Meanwhile, China's state news agency warned against rushing to implicate Russia in the downing of a Malaysian airliner over eastern Ukraine, but said those responsible must be brought to justice for the "intolerable terrorist attack".
World leaders demanded an international investigation after the airliner was downed with 298 people on board in a tragedy that could mark a pivotal moment in the worst crisis between Russia and the West since the Cold War. There were no survivors.
Two US officials said Washington strongly suspected the Malaysia Airlines Boeing 777 was downed by a sophisticated surface-to-air missile fired by Ukrainian separatists backed by Moscow.
The official Xinhua news agency said in an English-language commentary that officials from the United States, Australia and other Western countries had jumped to conclusions in pointing their fingers at the rebels in eastern Ukraine and for blaming Russia for the escalating violence.
"The accusation was apparently rash when the officials acknowledged they did not know for the time being who is responsible for the attack, while condemning Russia's military intervention," Xinhua said.
The news agency said the top priority at the moment was to co-operate to "find out the real culprits, if any".
"If the plane turned out to have been shot down by a missile, the perpetrators should be brought to justice despite their motives and excuses, as it was an intolerable terrorist attack," Xinhua said.
State media do not represent Chinese policy, but are indicative of government thinking. Commentaries issued in English are typically directed at a foreign audience.
China's Foreign Ministry earlier expressed shock and offered its condolences to the families of those on board Malaysia Airlines flight MH17 in a statement posted to its website. In a later statement, it confirmed that a Hong Kong resident was on board.
China's civil aviation authority has ordered all Chinese airlines to reroute their flights away from eastern Ukraine following the crash, Xinhua said in a separate report.