Updated

When U.S. President Barack Obama mentioned Bahrain as one of the Middle East's flashpoints of sectarian conflict, the Shiite-led opposition in the Gulf nation cheered and the kingdom's Western-backed Sunni rulers went on the defensive.

Bahrain's leadership said last week that the Arab Spring's smallest showdown had threatened to divide the island but insisted that the rifts were healing after nearly 32 months of clashes and simmering unrest.

The past days in Bahrain, however, suggest a different trajectory. A series of prison sentences — including a mass trial of 50 suspected backers of a militant cell — and the largest protest march in months all signal little progress toward reconciliation.

Bahrain's main Shiite party bailed out of talks with the government last month to protest the detention of a top opposition figure, Khalil al-Marzooq, a former deputy parliament speaker under investigation for allegedly encouraging anti-government violence.

Now, opposition leaders seem to be digging in even more — including joining more than 10,000 marchers last week in a major show of unity by the country's Shiite majority.

"From a distance, the Bahrain conflict may look limited and isolated," said Mustafa Alani, a political analyst at the Gulf Research Center in Geneva. "Look closer and you see the complexities."

That's because it draws in the big three in Gulf strategic affairs: Saudi Arabia as the main protector of Bahrain's ruling system, Iran as an offsite sympathizer of Bahrain's Shiites, and the U.S. for its deep ties in the country, the home base for the U.S. Navy's 5th Fleet.

Shiite Muslims, who comprise about 70 percent of Bahrain's population, resumed their fight for greater political rights in February 2011 as the Arab Spring spread. They claim they face second-class status with practices such as reserving most top political and military posts for allies of Bahrain's Sunni Muslim dynasty.

Sunni leaders have made some concessions, including expanding the powers of the elected parliament. But crackdowns and clashes persist. As part of the highly charged rhetoric, authorities blame bombings and escalating violence on "terrorist" factions allegedly directed by Iran — although no firm evidence has yet to be produced.

More than 65 people have died in the unrest, including some security forces. Shiite opposition leaders and rights groups place the toll closer to 100.

Washington doesn't want to cause any serious rifts in its relations with Bahrain's monarchy. But U.S. officials haven't remained silent on some issues, such as criticizing an edict last month that requires official permission for direct contact between political groups and foreign diplomats.

In a U.N. speech last week, Obama referred to "sectarian tensions that continue to surface in places like Iraq, Syria and Bahrain." That brought a swift response from Bahrain. Foreign Minister Khalid bin Ahmed Al Khalifa insisted "terrorist extremist groups" are trying to unravel centuries of Sunni-Shiite cooperation in his country.

But efforts to stamp out militant factions appear to be driving apart both sides as well.

On Sunday, a Bahrain court sentenced 50 people to prison terms of five to 15 years after a mass trial for alleged links to a group known as February 14 — named for the start of the current uprising in 2011 — that has been accused of deadly bombings and other attacks. Twenty of the defendants were convicted in absentia.

The charges included trying to topple the ruling system and having links to Iran. Iran's state-run IRIB radio reported that Bahrain's rulers continue to "ignore the righteous demands of the Bahraini nation" with thousands arrested since early 2011.

Such comments reinforce Gulf claims that Iran is guiding the protests in Bahrain. Iran has denied having any direct links to the unrest.

On Monday, meanwhile, a Shiite religious chanter was sentenced to 15 months in prison on charges of calling for "illegal" protests. On the same day, an appeals court reduced from 10 years to two years the sentences against two policemen found guilty in the fatal torturing of a protester.

"The government can't convince the international community that its judicial proceedings are fair and open," said Hadi al-Musawi, a senior figure in the opposition group Al Wefaq. "Reducing the sentences from the two policemen ... shows clearly that the government is not serious about reconciliation."