HAVANA (Reuters) - Cuba paraded troops and hundreds of thousands of citizens through its emblematic Revolution Square on Monday in a traditional show of nationalist fighting spirit in the face of steep economic and diplomatic challenges.

The event marked the 60th anniversary of the landing of the Granma yacht which brought the Castro brothers and their bearded rebels from Mexico to Cuba to start their revolution against a U.S.-backed dictatorship.

Troops wielding automatic rifles marched in lock step behind a replica of the Granma on Monday, followed by a sea of banner- and flag-waving Cubans, many bussed in and organized through their workplaces and neighborhoods.

“This is an important message of unity and strength,” said Rene Lazo, 66, who, like most, got up well before the crack of dawn to participate in the parade.

“This is going to be a difficult year but we will keep working hard to bring our people forwards”.

Communist-ruled Cuba fell into an economic recession in the second half of last year, its first since the collapse of the Soviet Union a quarter century ago, as its strategic ally Venezuela floundered.

Meanwhile its historic detente with the United States came under threat with the election of Donald Trump as President. Trump, who takes office on Jan. 20, has said he would unravel attempts to normalize relations unless he gets a “better deal”.

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All this is taking place as Cuba is also coming to terms with the loss of its revolutionary leader, Fidel Castro. While “El Comandante” had handed the presidency over to his younger brother Raul in 2008, he remained a key figurehead.

Some of those marching held up images of Castro or banners reading “We are Fidel”. While the parade normally takes place every five years on Dec. 2, it was postponed a month due to his death in late November.

“He may not be present physically but he is in all our hearts,” said Natalia Gonzales, who had painted “I am Fidel” on the foreheads of her three grandchildren.

Raul Castro and his family watched and waved at those marching from the foot of the towering monument to independence hero Jose Marti in the center of the square.

The mood on Monday was of defiance although many Cubans said they hoped there would not be a return of Cold War-era politics.

“We are braced for conflict with the USA, we always have been,” said 70-year-old Marcial Garcia. “But I hope Trump will instead follow the path ... towards normalization.”

Trump’s threat to gradual and still fragile detente could not come at a worse time for Cuba.

A tourism boom in part sparked by looser travel restrictions on Americans failed last year to offset dwindling oil shipments from Venezuela and less cash for Cuban doctors and other professionals working overseas.

“Everything is just very uncertain at the moment, so there’s more propaganda,” said Antonio Sosa, 50, an engineer who chose not to attend the parade. “You don’t see news on the news broadcast anymore, just speeches Fidel gave 30 years ago.”