Iran has hanged three men and a woman, a newspaper reported , in the latest of a series of executions that have drawn criticism from rights groups and European states.

Two of the men and the woman had been convicted of murder while the third man was executed for rape.

Murder, rape, adultery, and drug trafficking are among crimes punishable by death under Iran's Islamic sharia law, imposed since the 1979 revolution.

"The four convicted people, including a woman, were hanged on Wednesday morning inside the Evin prison in Tehran," said the state-run newspaper, Iran.

It said that Ghasem Yaghoubi had kidnapped and raped 19 young boys in a year. Amnesty International has protested to Iran over the number of executions, which according to its report in April had doubled to at least 177 people in 2006..

The number of executions, many in public, has risen since July with the launch of a summer crackdown on "immoral behaviour". During the campaign, police have arrested dozens of drug addicts, smugglers, rapists and murderers.

The crackdown has also included an initiative to confront women who fail to adhere to Iran's strict Islamic dress codes.