Extremist group al-Qaeda has sent a warning to Saudi Arabia’s crown prince that his efforts to liberalise the conservative kingdom are “sinful projects”.

“The new era of [Mohammad bin Salman] replaced mosques with movie theatres,” the Yemen-based al-Qaeda in the Arabian Peninsula (AQAP) said in a statement.

The group went on to condemn the prince for the Western “absurdities” which have “opened the door wide for corruption and moral degradation”.

Hundreds gather outside Downing Street to protest against Mohammad bin Salman's UK visit

The prince was given his title by his father King Salman a year ago. Since then he has sent shock waves through Saudi society, instigating wide-ranging social and economic reforms designed to wean the kingdom off its dependence on oil.

Cinemas have reopened, the country’s long-standing driving ban for women is due to end later this month, and the prince has even publicly criticised Saudi Arabia’s religious establishment as out of touch with the times and promised a return to a more “moderate Islam”.

The prince’s critics say the reforms are a smokescreen for his branch of the House of Saud to consolidate its power.

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Of particular ire to al-Qaeda, however, appears to be a World Wrestling Entertainment (WWE) event in the Saudi city of Jeddah which took place in April.

“[Foreign] disbelieving wrestlers exposed their privates and on most of them was the sign of the cross, in front of a mixed gathering of young Muslim men and women,” it said.

“The corruptors did not stop at that, for every night musical concerts are being announced, as well as movies and circus shows.”

The AQAP branch of the extremist organisation is currently battling Saudi forces who fight as part of an Arab coalition in neighbouring Yemen’s complex civil war.