Guatemalans who were deliberately infected with syphilis or gonorrhoea in medical tests in the 1940s are suing the US government for compensation.

Hundreds of Guatemalan prisoners, psychiatric patients and orphans were infected without their consent in a programme to study penicillin.

A class action lawsuit was filed by lawyers for the Guatemalans and their relatives.

The US apologised last year for the "reprehensible" experiments.

But lawyers said the Obama administration had not responded to a request for an out-of-court compensation settlement.

The tests were kept secret for decades, until a medical historian uncovered hidden records and made them public last year....