China released 10 foreign activists on Sunday night after the US had strongly criticised the treatment of human rights protesters during the Olympics.

The US said on Sunday it was “disappointed” at the way China had treated human rights protesters during the Olympics and called for the immediate release of eight American demonstrators detained in Beijing.

On the day of the closing ceremony of the Games, the US embassy in Beijing issued an unusually strong statement criticising Chinese authorities for their handling of protests and dissent during the fortnight.

“We are disappointed that China has not used the occasion of the Olympics to demonstrate greater tolerance and openness,” the statement said. The comments came before the release of 10 protesters.

The tough language employed by the US underlines the way the Beijing Games have at times been overshadowed by accusations of human rights abuses in spite of the successes of the striking stadiums, efficient organisation and China’s triumph over the US in medals.

The Chinese government has been heavily criticised for jailing a number of people who applied to hold demonstrations in government-chosen protest zones.

According to human rights groups, two women in their 70s were sentenced to a year in a “re-education through labour” camp after they applied to hold a protest, although the women have not been sent to the camp. Of 77 applications for protests, none were approved.

Such issues were not allowed to intrude on Sunday’s closing ceremony, which featured a reprise of the glittering mass performances that opened the games and a modest taster for the 2012 London Olympics that featured an unfolding double-decker bus and soccer star David Beckham.

China had “smoothly completed” its tasks in organising a “green, scientific and humanistic” games, declared Liu Qi, a leading Olympics organiser and a senior Communist party official.

Eight Americans and two other foreigners – a Briton and a German – have been detained in Beijing for between 10 and 14 days for holding demonstrations against Chinese policy in Tibet. They were among several small groups of foreigners who held protests over the past two weeks.

In the early stages of the Olympics, foreign protesters were immediately deported. However, the string of detentions since August 20 suggest the authorities have decided on a harder line.

The US embassy said the Chinese constitution established protection of human rights and that China had agreed to a number of international human rights standards. “We encourage the government of China to demonstrate respect for human rights, including freedom of expression and freedom of religion of all people – during the Olympic Games and beyond,” it said.

China’s foreign affairs ministry did not immediately comment.

The British Foreign Office confirmed the detention of a UK citizen and urged the Chinese government “to respect its commitment to freedom of expression”.