The harsh prison sentences meted out to three Saudi reformists who demanded a constitutional monarchy showed the red lines of the political reform process in the oil-rich kingdom.

"The harshness of the sentences was surprising," said a foreign diplomat posted in the Saudi capital. "One cannot find out what laws they (the defendants) breached."

Ali al-Demaini, Abdullah al-Hamed and Matrouk al-Faleh were sentenced on May 15 to nine, seven and six years of imprisonment respectively.

They figured among 116 other signatories of a petition addressed in December 2003 to the kingdom's rulers demanding a "comprehensive constitutional reform", including an elected parliament.

A dozen of the signatories were arrested in March 2004. All but the three sentenced in mid-May were released but only after pledging to no longer lobby publicly for reform.

"They (the regime) wanted to make an example, to show people that they have to think twice," said Khalid Dakheel, a professor of political science at King Saud university.

"They want to keep things under their control, to have reform at their own pace. They will be the ones to decide when and how far," the liberal political analyst said.

Authorities would decide the pace, as well as the extent and the framework of reform, while no one should interfere, he added.

It was following the terrorist attacks of September 11, 2001 in the United States that Crown Prince Abdullah bin Abdulaziz, the de facto ruler of the ultra-conservative kingdom, opted for careful reforms.

It was aimed at least in part at neutralising external criticism, coming mainly from the United States.

The ailing King Fahd, who has been hospitalised since last Friday, had previously established a Shura (consultative) council in 1992, but whose members are all appointed.

In January 2004, Abdullah summarised his philosophy of reform in calling for "moderation", while rejecting "stagnation and unwise adventures".

The most significant reform took place earlier this year when municipal elections -- involving only Saudi men - were held for the first time to choose half the members of 178 councils, while the others are appointed.

But "nobody knows what they mean by reform, what is the extent of these reforms", Dakheel said.

The next stage of reforms remains a mystery, he said, speculating it could involve electing half the members of the Shura council or allowing men to elect all members of the municipal councils.

Some officials indicated also that the next step might be allowing women to cast their vote in the next municipal polls, in four years' time.

But Dakheel seemed cautious about the continuation of the process of reform because the "regional and international environments are not conducive to change".

"It is feeding fear, suspicion and providing material evidence that change could really go very badly," he said, citing the examples of Lebanon and Iraq.

This climate thus works in favour of the regime as "people are very concerned about political stability in the country", Dakheel said.

"People are not satisfied with reform in this country, but ... the Saudis do not want to go through what the Lebanese or the Iraqis went through. So they think that under the circumstances, if the change will be slow, so be it," he added.

In the immediate future, Dakheel does not rule out a royal amnesty that would commute the sentences of the three reformists.

The diplomat said that "reform at this pace cannot go very far", pointing out that the contrary would amount to calling into question the foundations and even the very existence of the absolute monarchy.