A performance by Elton John sparked outrage among Morocco's anti-gay conservatives and tested the limits of the country's modernisation drive.

Islamists in the North African kingdom were furious at the gay pop star's visit, while the royal palace, government and his many fans backed his appearance last night.

Authorities had beefed up security with thousands of police and plainclothes officers but no riots or violence was reported, said Rabat's governor, Hassan Amrani.

Mr Amrani said about 50,000 people attended the free concert in a wealthy neighbourhood of the capital.

"He reminds me of my youth. I used to go to his concerts when I was a student in France," said Souda Bennani, 48, a pharmacist who knew many of Sir Elton's lyrics by heart.

Other entertainers performing at the May 21-29 festival include Sting, Mika and Carlos Santana and Arab music stars.

But in an apparent move to defuse possible tensions, Sir Elton was the only festival artist who was not scheduled to meet the local media.

In a sign of Sir Elton's popularity, several thousand of his fans appeared to know his lyrics by heart even though most people in the French and Arabic-speaking country know little or no English.

"He is a very big name in the music world, he's a great artist. And his private life is nobody's business," said Leila Hassan, a 43-year-old housewife.

The tension over the concert is part of a tussle between conservatives and modernisers in a nation that criminalises homosexuality but has long been famous for a swinging party scene.

Morocco has attracted gay celebrities such as designer Yves Saint Laurent and writer Paul Bowles, and recently saw the launch of its first gay magazine.

Across the Islamic world, strictly hidden, but sometimes tacitly tolerated traditions of homosexuality are surfacing fitfully - and Sir Elton's concert is the latest litmus test.

The public dispute between organisers for the Mawazine Festival that invited Sir Elton and the Justice and Development Party, or PJD, Morocco's largest authorised Islamist group, illustrates the growing rift between Western-leaning Moroccan authorities and the more conservative Muslim movements that are on the rise in the kingdom.

"This singer is famous for his homosexual behaviour and for advocating it," said Mustapha Ramid, a leader and spokesman for the PJD, the biggest opposition party with 40 MPs in parliament.

"We're a rather open party, but promoting homosexuality is completely unacceptable."

Mr Ramid said homosexuality was against Muslim values and feared Sir Elton would "encourage the phenomenon" and be a bad influence for Moroccan youth.

Like nearly all Arab and Muslim countries, Morocco is officially hostile to homosexuality.

Homosexual practices are a crime punishable by fines and prison sentences of six months to three years, but in practice, they are almost never applied and Morocco has a long history of leniency towards homosexuality or other practices forbidden by Islam, like alcohol.

Moroccan officials had dismissed the calls to ban Sir Elton from performing.

"We deal with artists and intellectuals for what they do, without taking into account their private life," said El Hassan Neffali, an organiser of the Mawazine Festival.

"Somebody's private life is one thing and their art or creative activities are another."

The festival is under the patronage of King Mohammed VI - a powerful gesture in a country that remains an absolute monarchy and where the king, whose family claims descent from Islam's Prophet Mohammed, is also "Amir al-Mumineen", or commander of the believers.

Moroccan officials said they backed the festival, along with dozens of others through the spring and summer, as a means to promote cultural diversity and openness in society.

The cultural drive, along with new schools, housing projects and a vast program to reform the official teaching of Islam, is viewed as part of the king's broader plan to modernise society while offering an alternative to the Islamist groups that have become the country's biggest political force.

In Egypt, tentative plans to book Sir Elton were cancelled this month. Mounir el-Wasimi, the head of the Egyptian musicians' union, warned against the possible visit, saying Sir Elton was "a symbol of homosexuals in the world".