By Rania El Gamal : Reuters

DUBAI: A senior member of the ruling family in the emirate of Ras al-Khaimah is being held at the ruler's palace, his son said on Tuesday, amid a tightening of restrictions on Islamists in the United Arab Emirates.
 
Sheikh Sultan al-Qassimi, a cousin of the ruler of the northern emirate who also heads an Islamist group whose members have been targeted by security authorities, was taken from his house by armed men on Friday night and has since been held at the ruler's palace.
 
News of the detention first came from activists who said he had been arrested by security services. His son said he had been taken to the palace of the Ras al-Khaimah ruler.
 
"My father has been arrested on Friday night. We were surprised when armed men came to the house. They took him to the palace of Sheikh Saud al-Qassimi," Sheikh Abdullah al-Qassimi told Reuters by telephone.
 
"He has been kept alone in a locked room with armed guards," he said after visiting Sheikh Sultan, denying that his father had been detained due to a family spat.
 
There has been no official comment and it was not immediately clear why Sheikh Sultan was being held. Police officials in Ras al-Khaimah could not be reached for comment.
 
Activists from Ras al-Khaimah said they believed Sheikh Sultan, who is chairman of the Islamist al-Islah (Reform) group, had been targeted because he had signed a petition sent to UAE leaders requesting the country's Federal National Council (FNC), an advisory body, be given more powers.
 
The UAE, an oil exporter, has not seen the protests that have toppled four Arab leaders since last year, thanks in part to its cradle-to-grave welfare system, but it has shown little tolerance towards dissent that could unsettle its own realm.
 
Jail terms have been imposed on activists who sought greater power for the FNC. In December, the UAE revoked the citizenship of six Islamist activists it described as posing a threat to national security.
 
The six men, all members of al-Islah, were detained earlier this month after refusing to sign a declaration to seek a new nationality within two weeks.
 
The UAE is wary that the rise of the Muslim Brotherhood in Egypt after the ouster of President Hosni Mubarak, once a close ally of the Gulf Arab state, could embolden its own Islamists.
 
Ras al-Khaimah, one of the poorer emirates of the seven-member UAE federation that includes business hub Dubai and oil-exporter Abu Dhabi, has been a source of occasional unrest for the UAE and the emirate is witnessing growing Islamist sentiment.
 
In 2003, the UAE federal government sent tanks into the emirate to subdue protests after the ouster of one of the ruler's sons and the emirate's crown prince, Sheikh Khalid.
 
A spat in 2010 between the current ruler, Sheikh Saud, and his half-brother, Sheikh Khaled, before the death of their father raised fears of a succession power struggle.
 
The closest emirate to Iran, Ras al-Khaimah sits near the Strait of Hormuz, through which 40 percent of the world's traded oil passes. Some analysts point to the emirate, which produced one of the Sept. 11 hijackers, as a scene of growing Islamism, although most say security risks are exaggerated.