The UN general assembly has overwhelmingly condemned the US economic embargo against Cuba, adding pressure on the Obama administration to abandon its 47-year-old policy.

The assembly today voted 187-3 in opposition to the embargo, with only Israel and the Pacific island nation of Palau siding with the US, as they did last year. The annual diplomatic ritual had extra resonance this year because of the slight thaw in Washington-Havana relations.

Cuba's foreign minister, Bruno Rodriguez, told the meeting in New York that the embargo had cost the island tens of billions of dollars and denied medical care to children. "The blockade is an uncultured act of arrogance."

He lamented that the new US president had failed to end an "ethically unacceptable" hangover from the cold war. "President Obama has a historical opportunity to lead a change of policy toward Cuba."

The White House has made cautious overtures to Raúl Castro's government – such as easing travel restrictions for Cuban Americans – but has maintained crippling trade and financial controls first imposed by the Kennedy administration in 1962.

Susan Rice, the US ambassador to the UN, said Rodriguez's statements were "hostile" and that the Obama administration wanted to engage with Havana and write "a new chapter to this old story".

Mainstream US thinktanks say Barack Obama's reforms are timid and fail to reset a relationship that soured soon after Fidel Castro's revolutionaries overthrew the US-backed dictator Fulgencio Batista 50 years ago.

"This is a start, but more, much more, needs to be done," said Sarah Stephens, director of the Centre for Democracy in the Americas. "Not because the UN says so, but because our country needs to embrace the world not as we found it in 1959 – or in 2008 – but as it exists today."

The embargo bans Cuban imports, greatly restricts US exports and deters foreign firms from doing business with the island, 90 miles off Florida.

As a senator, Obama opposed the embargo but hardened his position when running for president, not least because he needed the votes of anti-Castro Cuban exiles in Florida. In office, he has let Congress take the lead in easing restrictions while saying the embargo will remain until Havana releases political prisoners and improves human rights.

"The US realises that the embargo is an outmoded policy but Obama is not ready to do the hard work required to remove it entirely, which means that US policy will continue to consist of piecemeal changes," said Dan Erikson, author of The Cuba Wars and an analyst at the Inter-American Dialogue thinktank.

Even US allies such as Britain, Australia and Colombia side against the superpower, saying its Cuba policy is a cold war anachronism given US trade with undemocratic states such as China and Vietnam. One European ambassador called the embargo "demented".

Havana will claim a propaganda windfall from today's vote. Rogelio Polanco, its ambassador to Venezuela, told a seminar in Caracas that international solidarity was needed to rein in a global bully.

"The US's economic and military power, even if diminished, remains hegemonic," he said.

Fidel Castro has long blamed the embargo for the island's impoverishment but there has been greater official recognition of the shortcomings of socialist central planning since his brother Raúl took over the presidency last year, .

The infrastructure creaks, the average monthly wage hovers under $20 and there are chronic shortages of basic goods such as fruit, vegetables, meat, soap, shampoo and toilet paper. The island's trade deficit rose to $11.4bn (£6.9bn) last year.