A member of Abu Dhabi's ruling family was found innocent yesterday of the torture and rape of an Afghan in a case that embarrassed the Gulf Arab emirate and raised questions over human rights.

The judge reading the verdict at a court in the United Arab Emirates, the world's third largest oil exporter and a US ally, did not give a reason why Sheikh Issa bin Zayed al-Nahyan was exonerated of responsibility for abuse shown in a video first made public on US network ABC last year.

In the footage, which dates back to 2004, the Afghan man is seen being struck with an electric cattle prod, beaten with whips and a plank of wood with a nail in it, and driven over by a car at a desert location near the oasis of al-Ain.

ABC identified one of the people taking part in the abuse as Sheikh Issa.

But a lawyer for the sheikh, a son of UAE founder Sheikh Zayed, said his client was found to have "diminished liability" because two former business associates had drugged him then taken the video to extort money from him.

The two men, Lebanese-American brothers Bassam and Ghassan Nabulsi, were sentenced to five years in absentia and fined 10,000 dirhams (€1890) for what the judge said was drugging, recording and publishing a video and blackmail.

Sheikh Issa kissed his lawyer on the head after sentencing was announced but made no comment.

A Nepalese security guard shown in the video was also acquitted. A Syrian national was given one year in jail for beating the man and an Indian and a Palestinian were both sentenced to three years for sodomising him with a stick.