A series of trials under way in the neighboring Gulf states of Saudi Arabia and Bahrain offer a glimpse into the ongoing, silent war being waged by Iran against its regional rivals.

Bahrain is of particular interest to Tehran. The tiny island emirate is home to a Shi’a majority – ruled over by the Sunni Khalifa monarchy. Iranian officials often describe Bahrain as rightfully constituting the “14th province” of Iran. A Shi’ite insurgency was crushed in March 2011, following the entry of Saudi, Kuwaiti and United Arab Emirates forces. Tensions remain high.

Saudi Arabia, meanwhile, is one of Iran’s main regional rivals.

The two, both major oil-producing states, are separated by sectarian loyalties, strategy toward the West and straightforward geopolitical competition for dominance in the energy-rich Gulf region.

The latest revelations suggest that the long-standing use by the Iranian regime of subversion and irregular warfare as tools of policy in the Gulf – as elsewhere – is proceeding apace.

In Bahrain, recent revelations have centered on two cases.

In the first, a Bahraini citizen convicted in July 2011 of transferring “military information and identifying sensitive sites in Bahrain” to Iranian diplomats in Kuwait had his 10-year sentence confirmed this week.

According to a statement from the court, the man, who has not been named, sought to photograph “military and economic installations” in Bahrain, as well as the homes of individuals employed at the US Juffair Naval Base on the island. The Juffair Base is the main site in the Gulf offering onshore services for the US Navy’s 5th Fleet.

The “diplomats” in question were identified as members of the Iranian Revolutionary Guards Corps. IRGC members have a long history of posing as Iranian diplomats and consular staff.

In the second, more recent case, Bahraini authorities in late February arrested eight Bahraini citizens accused of membership in a cell established by the Revolutionary Guards to plan and carry out attacks on Bahrain’s international airport, Interior Ministry and other public facilities, and to assassinate Bahraini officials.

The Bahrainis identified an IRGC official, code-named “Abu Naser” as the head of this group. They claimed to have captured a host of evidence, including electronic equipment, incriminating the arrested men. The authorities also maintained that the members of the cell attended IRGC training camps in Iran and Hezbollah- run centers in Iraq.

In Saudi Arabia, meanwhile, the authorities in March arrested 16 Saudi citizens, an Iranian and a Lebanese, similarly on suspicion of membership in a cell established by Iranian intelligence elements, and tasked with gathering information and providing documents concerned with “installations and vital areas” in the kingdom.

The Saudi citizens all hail from the country’s 2 million strong Shi’a minority.

The Iranians, predictably, have denied all the accusations. Iran and its regional mouthpieces accuse the Gulf states of seeking to justify their repression of Shi’a communities.

Thus, the opposition al-Wifaq party in Bahrain denounced the latest arrests. In Saudi Arabia, meanwhile, 37 Shi’a clerics issued a statement accusing the authorities of escalating sectarian tension as a way of diverting public attention from other issues.

It is indisputable that both the Shi’a majority in Bahrain and the Saudi Shi’a minority face real repression and discrimination. The existence of real and justified grievances does not, however, cancel out the evidence of Iranian subversive activity.

And it is also clear that the evidence emerging regarding the activities of the IRGC in both countries follows a pattern familiar both from experience and from Iranian activities elsewhere in the region and beyond it.

The use made by Iran of local Shi’a communities, and the subsequent engagement of those communities in political violence on its behalf, is no longer in dispute. Past precedent suggests that Iran seeks not only to recruit participants for paramilitary activity. Rather, Tehran also wishes to build political influence and power through the sponsorship of Shi’a Islamist movements.

Their efforts in Bahrain are not of recent vintage. As far back as 1981, the proxy Islamic Front for the Liberation of Bahrain launched a failed coup attempt, with the support and probably under the direction of Iran and the IRGC.

The Iranians have spent many patient years building up assets and clients within the Bahraini opposition.

Hasan Mushaima, the Shi’a Islamist leader of the Haq movement, was openly pro-Iranian and known to have strong links with the Iranian regime. Mushaima was jailed for life after the 2011 unrest.

His son, along with five others, was convicted in absentia in 2012 for involvement in an earlier Tehran sponsored terror cell.

Both the mainstream Wifaq opposition movement and the more radical Coalition for a Republic have pro-Iranian elements within them.

The latter includes the Bahraini Islamic Freedom Movement. The leader of this openly pro-Iranian body, Saeed Shihaby, was discovered in 2011 to be working in London in premises owned by the government of Iran.

The latest revelations of Iranian subversion in the Gulf come against a background of frenetic activity by Tehran elsewhere.

Just this week, Lebanese-Swedish Hezbollah member Hossam Taleb Yaacoub was convicted of gathering information on Israeli holidaymakers in Cyprus prior to the bombing at Burgas.

A build up of Hezbollah and IRGC personnel in Damascus, according to a report in Al-Arabiya, is now under way, in a determined attempt to hold back recent rebel advances.

An Iranian ship carrying weapons for Shi’a rebels in north Yemen was seized last month.

Tehran is seeking to guard and expand the perimeters of the client and proxy structure it has built, at a time when a rival Sunni Islamism is having its moment.

Iran’s silent war in the Gulf forms an important front in this larger campaign.

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