The former Cuban leader, Fidel Castro, has given his qualified endorsement to the restoration of diplomatic relations between his country and the US. In a letter to the Cuban Student Federation, published in the state-owned newspaper Granma, he wrote, “I don’t trust the policy of the US, nor have I exchanged a word with them, but this does not mean I reject a peaceful solution to conflicts.”

The 88-year-old, who has not been seen in public for more than a year, said in the letter, dated Monday 26 January: “We will always defend cooperation and friendship with all the people of the world, including with our political adversaries.”

The letter was Castro’s first acknowledgment of last month’s move by the US and Cuba to normalise relations after more than half a century of hostility. Following a prisoner exchange in December, officials from both sides met last week in Havana for high-level negotiations about establishing economic ties and re-opening embassies in each other’s capitals. Neither Fidel Castro nor his brother Raul, the current Cuban President, was involved in the talks.

Though the long-standing US trade embargo is still in force, President Barack Obama said he would lift certain sanctions and loosen the travel restrictions on US citizens visiting Cuba. Both sides said the meeting was productive, but talks reportedly stalled over Cuba’s call for the US to stop funding dissident rivals to the island’s Communist regime, and over US demands that Cuba give up American fugitives hitherto sheltered by the Havana government.

In pictures: Timeline of US and Cuba relations Show all 19 1 /19 In pictures: Timeline of US and Cuba relations In pictures: Timeline of US and Cuba relations Cuba timeline July 1953: Fidel Castro begins a revolutionary campaign against the regime of Cuban President Fulgencio Batista In pictures: Timeline of US and Cuba relations Cuba timeline January 1959: Castro and Che Guevara enter Havana after a successful final offensive. Batista flees, and Castro becomes prime minister, ruling by decree In pictures: Timeline of US and Cuba relations Cuba timeline October 1960: Castro’s reforms sees hundreds of US businesses in Cuba nationalised and their owners not compensated. In December, US US breaks off diplomatic relations and imposes a trade embargo In pictures: Timeline of US and Cuba relations Cuba timeline April 1961: Cuban exiles launch the Bay of Pigs invasion with US backing In pictures: Timeline of US and Cuba relations Cuba timeline October 1962: A 13-day confrontation known as the Cuban missile crisis begins when Castro allows the USSR to deploy nuclear missiles on the island. Generally regarded as the closest the world has come to nuclear war In pictures: Timeline of US and Cuba relations Cuba timeline 1962: US President John F Kennedy signs off a naval blockade Getty Images In pictures: Timeline of US and Cuba relations Cuba timeline April 1980: A sharp downturn in the Cuban economy and Castro temporarily lifting restrictions sees around 125,000 people, many of them released convicts, flee to the US In pictures: Timeline of US and Cuba relations Cuba timeline February 1996: Cuba shoots down two US aircraft operated by Miami-based Cuban exiles, prompting the US to make its trade embargo permanent In pictures: Timeline of US and Cuba relations Cuba timeline June 2001: The case of the “Cuban Five” begins, as five spies in Miami are convicted of providing intelligence to the Havana government In pictures: Timeline of US and Cuba relations Cuba timeline Nov 2001: US sells $30m of food to the Cuban government to assist in the aftermath of Hurricane Michelle, which killed 22 people, the first food export between the countries for more than 40 years In pictures: Timeline of US and Cuba relations Cuba timeline Oct 2003: US President George W Bush announces fresh anti-communist measures, including tightening the travel embargo and creating a new government body, the Commission for Assistance to a Free Cuba In pictures: Timeline of US and Cuba relations Cuba timeline Aug 2006: President Bush seizes the opportunity of President Castro’s illness and a handover of powers to Raul Castro, urging Cubans to work towards democratic change In pictures: Timeline of US and Cuba relations Cuba timeline Feb 2008: Raul Castro officially takes over as president. Washington responds by saying its trade embargo will remain in force unless free and fair elections are held In pictures: Timeline of US and Cuba relations Cuba timeline Dec 2008: A poll by Florida International University suggests for the first time that a majority of Cuban-Americans living in Miami want an end to the embargo In pictures: Timeline of US and Cuba relations Cuba timeline April 2009: President Obama lifts restrictions on family travel to Cuba In pictures: Timeline of US and Cuba relations Cuba timeline Dec 2009: US aid worker Alan Gross is detained in Cuba on suspicion of spying for Washington AP In pictures: Timeline of US and Cuba relations Cuba timeline Nov 2010: American Ballet Theatre performs in Cuba for the first time in 50 years, the most high-profile in a series of cultural exchanges In pictures: Timeline of US and Cuba relations Cuba timeline Sep 2012: Cuba hints at its willingness to do a deal with Washington on the Gross case In pictures: Timeline of US and Cuba relations Cuba timeline December 2013: President Obama and Raul Castro shake hands at the memorial service for Nelson Mandela. Castro says in English: “Mr President, I am Castro.” It was hailed in Cuba as “the beginning of the end” for what were then described as “US aggressions”

The US cut off diplomatic ties with Cuba in 1961, as the Castro regime’s Cold War sympathies became clear. Two years later, the Kennedy administration backed a disastrous attempt to invade the island at the Bay of Pigs. Castro survived multiple assassination attempts and outlived many of his US presidential enemies, remaining in power until 2008, when he stepped down due to illness after 49 years in power and ceded leadership to Raul, who is now 83.

Despite his equivocal response to recent developments, it is widely believed that Fidel must have given his approval to the discussions with the US before Havana agreed to them. In his letter, he appeared to praise his brother’s decision to engage with the US, saying the Cuban president had “taken the pertinent steps in accordance with his prerogatives and the powers given to him by the National Assembly the Communist Party of Cuba.”

The former leader has often commented on Cuban affairs in letters since he stepped down, and this week’s 1,200-word missive contained familiar references to his revolutionary idols such as Lenin and Mao. Until its publication, Castro’s silence regarding restored US-Cuban relations had been seen either as opposition to the news, or as a sign that he was in increasingly poor health.