Unesco, the United Nations' culture and education agency, has delayed awarding a prize for life sciences named after the leader of Equatorial Guinea, whose government has a reputation for corruption and human rights abuses.
Human rights and civil society groups have said Unesco was enabling Teodoro Obiang Nguema Mbasogo to "launder" his international reputation by funding the $3m (£2m) prize instead of using the cash to improve the living standards of his people.
Mr Obiang took control of Equatorial Guinea after a coup in 1979. Under his rule, the country – listed among the 12 most corrupt countries by Transparency International – has leapt from small-scale cocoa producer to major oil supplier.
Irina Bokova, Unesco's director general, said no new date had been set for awarding the prize and urged the agency to review the matter.