World leaders have paid tribute to the former Cuban leader and revolutionary Fidel Castro who has died aged 90.

The incumbent Cuban President Raul Castro announced his brother's death at 10:29pm on state television on Friday. He ended the announcement by shouting the revolutionary slogan: “Toward victory, always!”

Castro stepped aside as leader 10 years ago after suffering a severe gastrointestinal illness, and before his 90th birthday in August he told supporters he expected to die soon.

Leaders and politicians from across the world have reacted to the death of the firebrand leader who headed a rebel army to unlikely victory in Cuba, embraced Soviet-style communism and defied the power of 10 US presidents during his near 50-year rule.

Mikhail Gorbachev, the former Soviet Union leader, which acted as an economic and political prop for Cuba, praised Castro for "strengthening" his island nation.

"Fidel stood up and strengthened his country during the harshest American blockade, when there was colossal pressure on him and he still took his country out of this blockade to a path of independent development," Interfax news agency quoted Mr Gorbachev as saying.

In a telegram of condolence to the Cuban President, Russia's Vladimir Putin hailed Castro as the "symbol of an era". "The name of this distinguished statesman is rightly considered the symbol of an era in modern world history... Fidel Castro was a sincere and reliable friend of Russia," the Kremlin is quoted as saying.

Fidel Castro: Life in pictures Show all 27 1 /27 Fidel Castro: Life in pictures Fidel Castro: Life in pictures Mandatory Credit: Photo by Harry Laub/imageBROKER/REX (7454795a) Painted wall with the flag of Cuba and the words Viva Fidel, Santiago of Cuba, Santiago de Cuba Province, Cuba VARIOUS Rex Fidel Castro: Life in pictures Fidel Castro in Havana, Cuba Rex Fidel Castro: Life in pictures Cuban president Fidel Castro looking at a rifle during a visit in North Vietnam during the Vietnam war Getty Fidel Castro: Life in pictures Cuban President Fidel Castro in Matanzas, Cuba, on the 46th anniversary of the assault on the Moncada Barracks by Castro's rebels. The attack marked the beginning of the Cuban revolution, which eventually propelled Castro to power Getty Fidel Castro: Life in pictures Fidel Castro with his first wife Mirta and his son Fidelito Rex Fidel Castro: Life in pictures Fidel Castro at his 'Guerrilla Man of Time' book launch in Havana, Cuba Rex Fidel Castro: Life in pictures Fidel Castro Rex Fidel Castro: Life in pictures Cuban President Fidel Castro delivers a speech attacking media organizations and groups opposed to his government in the wake of rumours of his death Getty Fidel Castro: Life in pictures Fidel Castro playing Basketball Rex Fidel Castro: Life in pictures Watched by Russian premier Nikita Khrushchev, Cuban dictator Fidel Castro takes a photograph of Moscow during his first visit to Russia Getty Fidel Castro: Life in pictures Cuban president Fidel Castro attends a protest against the US embargo of Cuba Getty Fidel Castro: Life in pictures Fidel Castro and Osvaldo Dorticos Torrado talking to Cuban medical staff who are going to Peru to help with the aftermath of an earthquake Getty Fidel Castro: Life in pictures Cuban revolutionary leader Fidel Castro relaxing at a sugar plantation near Havana, surrounded by children Getty Fidel Castro: Life in pictures Cuban President Fidel Castro presides over a massive May Day demonstration at Havana's Plaza de la Revolucion (Revolution Square Getty Fidel Castro: Life in pictures Cuban leader Fidel Castro is presented with an invitation to the New York Press Photographer's Ball, in New York City Getty Fidel Castro: Life in pictures Fidel Castro, Prime Minister of the Cuban Revolutionary government and first secretary of the Cuban Communist Party, and Ernesto Guevara known as Che, minister of Industry in Havana, Cuba Getty Fidel Castro: Life in pictures Cuban President Fidel Castro waves to participants of the traditional May Day parade attended by thousands of people in Havana's Plaza of the Revolution Getty Fidel Castro: Life in pictures Cuban Prime Minister Fidel Castro with Argentine guerrilla leader Ernesto Che Guevara Getty Fidel Castro: Life in pictures Pope Benedict XVI meets with former Cuban President Fidel Castro at the Vatican embassy in Havana, Cuba Getty Fidel Castro: Life in pictures Cuban revolutionary Fidel Castro and Soviet politician Nikita Sergeyevich Khrushchev in Moscow Getty Fidel Castro: Life in pictures Iraqi vice-president Saddam Hussein, stands with Cuban President Fidel Castro and Defense minister General Raul Castro in Havana, during his visit to Cuba Getty Fidel Castro: Life in pictures Iranian President Mahmoud Ahmadinejad and former Cuban leader Fidel Castro Rex Fidel Castro: Life in pictures Cuban President Fidel Castro listens to Pope John Paul II as they walk on the tarmac of the Jose Marti International Airport in Havana Getty Fidel Castro: Life in pictures Fidel Castro with Chavez in Cuba Getty Images Fidel Castro: Life in pictures Fidel Castro greets Zimbabwe's President Robert Mugabe in Havana Getty Fidel Castro: Life in pictures Fidel Castro with Gabriel Garcia Marquez in 2000. The two friends first met in 1959 AFP/Getty Images Fidel Castro: Life in pictures Mandela salutes the crowd alongside Fidel Castro in Matanzas Getty

In the US, President Barack Obama, who improved relations between the US and Cuba with a historic visit in March this year, said the United States is extending "a hand of friendship to the Cuban people" in the wake of Castro's death.

In a statement Mr Obama said that "history will record and judge the enormous impact of this singular figure on the people and world around him". He noted that "discord and profound political disagreements" had marked the relationship between the United States and Cuba for nearly six decades, adding he "worked hard to put the past behind us."

Meanwhile, President-elect Donald Trump offered a scathing attack against Castro, dubbing him a "brutal dictator".

"Today, the world marks the passing of a brutal dictator who oppressed his own people for nearly six decades. Fidel Castro’s legacy is one of firing squads, theft, unimaginable suffering, poverty and the denial of fundamental human rights," Mr Trump said in a statement, following his initial curt commentry on Twitter.

In the UK, Foreign Secretary Boris Johnson described Castro as a "historic if controversial figure" and his death marked "the end of an era for Cuba and the start of a new one for Cuba's people".

Prominent figures from the left of British politics responded to the death, including Labour leader Jeremy Corbyn who told the Press Association: "Fidel Castro was a massive figure in the history of the whole planet."

Former London mayor Ken Livingstone called Castro an "absolute giant of the 20th century", and blamed the US for the restrictions on civil liberties under his leadership. He told BBC Radio 4's Today programme that Cuba could reform now it was not under the threat of American invasion "even if Trump goes a little bit bonkers".

Canadian President Justin Trudeau, who was in Cuba earlier this month but did not meet with Castro, said he received the news with "great sadness" and called the revolutionary a "long-time friend of Canada and my family".

The ties between Castro and the Trudeau family are decades-old, with Castro an honorary pallbearer at Mr Trudeau's father's funeral in 2000.

In a more reserved statement, French President Francois Hollande said Castro embodied Cuba's revolution in both its "hopes" and its later "disappointments".

"An actor of the Cold War...he represented, for Cubans, pride in rejecting external domination. France, which denounced human rights violations, has always contested the embargo imposed on Cuba by the US," he said.

Enrique Pena Nieto the President of Mexico, where Castro fled and organised a rebel band that returned to Cuba 1956, said: "Fidel Castro was a friend of Mexico, promoter of a bilateral relationship based on respect, dialogue and solidarity."

Bashar al-Assad, the Syrian President, has sent his condolences to Raul Castro and praised his brother's legacy. A statement said he received the news of his death with great "sadness and sorrow".

"Castro's name will remain immortal and inspire generations of people aspiring for genuine independence and freedom from colonialism and hegemony," said Mr Assad.

Chinese President Xi Jinping said Castro "made immortal historical contributions to the development of socialism around the world."

"With his death, the Chinese people have lost a close comrade and a sincere friend. His glorious image and great achievements will be recorded in history forever," Xi said in a telegram to Raul Castro, state broadcaster CCTV said.

Pope Francis offered "my sense of grief to your excellency and family" in a telegram to Raul Castro. In a sign of his personal esteem, the Pope signed the telegram, breaking from the Vatican's usual practice of having the secretary of state send such messages. Francis met Castro during the papal visit to Cuba in September 2015.

A statement from the Spanish government hailed Castro as "a figure of enormous historical importance" as a small crowd of both pro- and anti-Castro supporters met in front of the Cuban embassy in Madrid.

"As a son of Spaniards, former president Castro always maintained close relations with Spain and showed great affection for his family and cultural ties. For this reason Spain especially shares the grief of Cuba's government and authorities," the government statement said.

Lebanon's militant Hezbollah group described Mr Castro as a great leader. Ammar al-Moussawi, who is in charge of the group's international relations, lauded Castro as "a historic symbol whose life was a lighthouse to all revolutionaries around the world."

Castro will be cremated this afternoon in Cuba, where nine days of national mourning have been declared.

That Castro lived until 90, having survived multiple attempts on his life, was something he said he “never imagined“ when he briefly emerged from seclusion earlier this year to deliver a farewell speech. “Soon I’ll be like all the others,” Castro said. "To all our turn must come.