Cuba’s new president has promised to modernize the country’s economy and make the government more responsive to its people, even as he pledged to uphold the values of the country’s socialist revolution.

Miguel Díaz-Canel was sworn in as president on Thursday, becoming the island’s first leader without the Castro surname for the first time in almost 60 years.

At a functionalist conference centre in Havana, Díaz-Canel, 57, read a brief speech which sought to reconcile revolutionary continuity with a recognition of the need for change. He said there would be no “capitalist restoration”, but promised to make better use of the internet and push on with “the modernization of our social and economic model”.

He finished his address with the familiar rhetorical flourish: “Socialism or Death! We will triumph!”

Raúl Castro, 86 – who stood down as president after 12 years in the office but remains first secretary of the Communist party – embraced Díaz-Canel, and gave his presidency a ringing endorsement.

But he left no doubt where power still lies. In an uncharacteristically long speech, in which he repeatedly joked and went off script, Castro emphasised the need to fight corruption – and said he would stay on to guide his successor.