The international community reacted with alarm this week as Saudi Arabia and the United Arab Emirates, under the auspices of the Gulf Cooperation Council (GCC), sent troops to Bahrain to help the usually sleepy kingdom contain the violent protests which have paralyzed it over the past month.

The United Nations released a statement saying that Secretary General Ban Ki-moon was "troubled" by the deployment of the Peninsula Shield Force and that the arrival of Saudi and UAE troops had been noted with "concern." Ban called on all those involved to "exercise maximum restraint."

Around 1,000 Saudi troops and 500 UAE policemen crossed the causeway between Saudi Arabia and Bahrain on Monday.

The United States admitted to being "shocked" by the move but rejected Iran's assertion that the entry of foreign troops into Bahrain was an invasion. The US declined to call for a withdrawal of the GCC troops from Bahrain, the country which hosts the headquarters of the US Fifth Fleet.

Iran vociferously criticized the deployment, the first cross-border intervention since a wave of popular protests began to spread across the Arab world two months ago. It accused the GCC states of "meddling" in Bahrain's internal affairs and said the presence of foreign troops would only further complicate the situation in the small Gulf kingdom.

Shiite protests add to unease in Saudi Arabia

Protests by Bahrain's Shiite-led opposition have already led to a number of people being killed since they erupted a month ago, and the violence escalated at the weekend when thousands of unarmed protesters poured into the financial district of the capital, Manama. Security forces responded with tear gas and rubber bullets, leaving hundreds wounded.

The Shiite uprising in Bahrain has been cited by Saudi Arabia as the cause of its own unrest in its Eastern Province, where the Saudi Shiite minority lives.

Earlier this month, a number of small-scale Shiite protests in the Eastern Province were met with a column of armored cars, but no casualties were reported as the protests were broken up. Saudi King Abdullah then accused the Shiite opposition in Bahrain of inciting the Saudi minority and told Bahrain's King Hamad that if he did not put down the uprising then Saudi Arabia would.

"It is being said in some quarters in Saudi Arabia that the deployment is more to send a signal to the Shiite movements in the Eastern Province about the seriousness of Saudi intentions to crack down, rather than to physically protect the al Khalifa regime, whose police forces are by and large well-equipped and loyal," Steffen Hertog, a Saudi Arabia expert at the London School of Economics and Political Science, told Deutsche Welle.

"Although we don't know for sure, it's likely that Saudi Arabia took the leadership on the deployment."

Iranian influence in show of force

The Sunni monarchies throughout the Persian Gulf are extremely wary of Shiite influence growing in the region and believe that the Shiite theocracy in Iran represents the biggest threat to their continued control, power and wealth in the region.

Iran has been accused of having a hand in inciting the restive Shiite minorities in Arab counties to rise up against the Sunni regimes which have ruled them, in some cases, for centuries.

"This is always a concern on the Saudi side, although fears of Iranian involvement are usually overblown," Hertog said. "The political agendas of most Shiite movements are local, even if their theological allegiance is often to Shiite clergy in Iraq or Iran."

"While there are some connections between Iran and some factions of the Bahraini and Saudi Arabian Shiite groups, there is no evidence of Iranian hands behind this revolt and even US Defense Secretary Robert Gates has told the Bahrainis this," Guido Steinberg of the German Institute for International and Security Affairs told Deutsche Welle.

"However it serves Riyadh's purposes to present this link," he added.

Bahrain's Shiite opposition alliance has rejected claims that it has links to Iran and has dismissed accusations that it wants to overthrow the monarchy. It says its aims are to replace the current government, an end to corruption and to secure greater representation for the Shiite majority.

However, radical Shiite groups in Bahrain - thought to be connected to Tehran - have called for the end of the al Khalifa dynasty and for the creation of a republic.

Regional analysts believe that the deployment of the Peninsula Shield Force is therefore a message to Iran and the more radical elements in Bahrain's Shiite majority that the GCC - and Saudi Arabia in particular - will not let the Bahraini regime fall, either from internal or external pressure.

Further escalation cannot be ruled out

"Bahrain has been unstable since 1979 and suffered terror attacks orchestrated by Iran and domestic Shiite groups in the 1980s, but the regime has survived by brutally fighting for its survival so there is little chance that it will fall at this time," Steinberg said. "Besides, Saudi Arabia won't let it."

What remains a concern for the states in the Persian Gulf - and the wider international community - is whether any increased involvement by the Saudi-led deployment will lead to an escalation of violence rather than a diffusion of tensions.

"I believe there is some readiness to escalate; there have been violent crackdowns in the Saudi Eastern province before in the 1980s, and they want to avoid the precedent of a GCC monarchy falling at almost all costs," said Hertog.

"However, it currently looks less likely that a full escalation with dozens or hundreds of deaths would happen, because the coercive military resources are mostly on the side of the Bahraini regime and most of the opposition is not armed."

Author: Nick Amies

Editor: Rob Mudge