New Cuban President Miguel Diaz-Canel on Thursday became the country's first leader in nearly 60 years who is not named Castro, pledging continuity for the Caribbean island during the historic transition of power.

The silver-haired Diaz-Canel — a top Communist Party figure who has served as first vice president since 2013 — assumed power from Raul Castro, who himself took over from his elder brother Fidel, father of the 1959 revolution.

In his own half-hour speech to the nation, Diaz-Canel pledged to preserve Cuba's communist system, while gradually reforming the economy and making the government more responsive to the people.

"There's no space here for a transition that ignores or destroys the legacy of so many years of struggle," Diaz-Canel said, Associated Press (AP) reported. "For us, it's totally clear that only the Communist Party of Cuba, the guiding force of society and the state, guarantees the unity of the nation of Cuba."

He said he would work to implement a long-term plan laid out by the National Assembly and Communist Party to permit moderate growth of private enterprises like restaurants and taxis, while leaving the economy's most important sectors — energy, mining, telecommunications, medical services and rum- and cigar-production — in the hands of the state.

"The people have given this assembly the mandate to provide continuity to the Cuban Revolution during a crucial, historic moment that will be defined by all that we achieve in the advance of the modernization of our social and economic model," Diaz-Canel said.

As the historic handover played out live on state TV, Cubans across the island were glued to their screens, watching at home or at work as the former engineer took his seat at the table, becoming the island's first president born after the revolution.

Diaz-Canel was voted in by the National Assembly on Wednesday, and the result was formalized on Thursday. His appointment has many in the country of more than 11 million people — where the average monthly salary is $30 — hoping he will push through reforms that will improve their daily lives.

Diaz-Canel received congratulations from the leaders of China, Russia, Britain and Spain and across Latin America, including from Venezuela's President Nicolas Maduro, a close ally of Cuba. But the United States, with whom Raul Castro launched a rapprochement and renewed diplomatic ties in 2015, was less welcoming.

"We are disappointed that the Cuban government opted to silence independent voices and maintain its repressive monopoly on power, rather than allow its people a meaningful choice through free, fair and competitive elections," State Department spokeswoman Heather Nauert said, as reported by Agence France-Presse (AFP).

"Cuba's new president should take concrete steps to improve the lives of the Cuban people, to respect human rights and to cease repression and allow greater political and economic freedoms."

The National Assembly erupted into applause as the result was read out, with delegates smiling and shaking hands warmly with Castro and Diaz-Canel. As he walked to the front of the chamber, Diaz-Canel high-fived the front row of delegates and embraced Castro as he took the stage. Then the 86-year-old raised his successor's left arm in the air in victory, prompting another wave of applause from the delegates — some of whom were in civilian attire, while others wore military fatigues.

It was a historic, though understated, handover. As Castro got up from the seat he has occupied for the past 12 years, it was immediately taken by Diaz-Canel, a man nearly 30 years his junior who has spent years climbing the party ranks. Next to him was the empty seat once occupied by Fidel, who died in 2016. Between them, the Castro brothers made Cuba a key player in the Cold War and helped keep communism afloat despite the collapse of the Soviet Union.

Raul has been in power since 2006 when he took over after illness sidelined Fidel. Thursday's handover took place on the anniversary of the 1961 Bay of Pigs invasion when Fidel's forces defeated 1,400 U.S.-backed rebels seeking to overthrow him.