Saudi Arabia's new defence minister, Prince Salman bin Abdulaziz, believes democracy is ill-suited to the conservative kingdom and advocates caution on social and cultural reform, according to a 2007 U.S. diplomatic cable released by WikiLeaks.

The 76-year-old was appointed to the post on Saturday after his elder brother, Crown Prince Sultan, who had been defence and aviation minister for five decades, died in New York last month.

Veteran Interior Minister Prince Nayef became crown prince in a choice that illustrated King Abdullah's concern for continuity and stability in the world's top oil exporter.

Prince Salman, governor of Riyadh province for nearly 50 years, now controls the top-spending ministry in Saudi Arabia, which has long used arms purchases to turn its military into one of the best equipped in the Middle East and to bolster ties with Western allies such as the United States, Britain and France.

He is one of the most senior members of the al-Saud ruling family which founded and still dominates the desert kingdom in alliance with conservative religious clerics.

In a royal family that bases its right to rule on its guardianship of Islam's holiest sites in Mecca and Medina, Salman is reputed to be devout and relatively outward-looking.

He's intelligent, political, in touch with the conservative base, but also quite modern-minded, said a former diplomat in Riyadh interviewed about the kingdom's succession process.

Since 1962, Salman has served as governor of Riyadh, and has more to do with foreign governments than many senior royals.

Another former diplomat said Salman had always been very helpful in resolving difficulties facing individual Westerners in a nation where expatriates form 30 percent of the population.

In a meeting with the U.S. ambassador in March 2007, described in a cable released by WikiLeaks, Salman said the social and cultural reforms instigated by King Abdullah had to move slowly for fear of a conservative backlash.

He also argued against the introduction of democracy in the kingdom, citing regional and tribal divisions, and told the ambassador that a solution to the Palestinian-Israeli conflict was necessary for Middle East stability.

ROYAL POWER

With his imposing figure and strong, bearded features, Salman is the prince who is said to resemble his father, King Abdulaziz Ibn Saud, more closely than do any of his brothers.

Ibn Saud recaptured his family's old stronghold of Riyadh in 1902 with a small band of followers fired by an austere vision of Islam, setting off a three-decade campaign of conquest that carved out the modern borders of a kingdom founded in 1932.

As one of the so-called Sudairi seven, the brothers born to Ibn Saud by his favourite wife Hassa bint Ahmed al-Sudairi, Salman has been at the centre of royal power for decades.

His full brothers in a family of more than 30 half-brothers include the late King Fahd and Crown Prince Sultan, the new Crown Prince Nayef and Prince Ahmed, deputy interior minister.

Salman was born in 1935 in Riyadh, then a mudbrick oasis town deep in the interior of a new kingdom that had not yet discovered oil, depending instead on revenue from pilgrims to Mecca and Medina, date farming and camel herding.

Yet his son, Prince Sultan bin Salman, became the first Arab astronaut, flying on the U.S. space shuttle Discovery in 1985.

Prince Sultan is now the kingdom's tourism minister while

another son, Prince Abdulaziz, is the deputy oil minister.

In his five decades administering Riyadh and its surroundings, Salman oversaw the development of the capital from a large desert town into a metropolis of 4.6 million people.

Prince Salman was taught in the princes' school set up in Ibn Saud's palace by the imam of the Grand Mosque of Mecca, signalling the importance that Ibn Saud attached to the centrality of pure Islamic belief in the kingdom he created.

(Reporting By Angus McDowall; Editing by Alistair Lyon)