DUBAI, United Arab Emirates (AP) — It’s become a nightly duel in Bahrain: Security forces and anti-government protesters waging hit-and-run clashes in one of the simmering conflicts of the Arab Spring.

So far, the skirmishes have failed to gel into another serious challenge to the Gulf nation’s Western-backed monarchy after crushing a reform rebellion months ago. But there are sudden signs that Shiite-led demonstrators could be poised to raise the stakes again on the strategic island, which is home to the U.S. Navy’s 5th Fleet.

Hundreds of demonstrators Wednesday made their boldest attempt in months to reclaim control of a central square in the capital Manama, which was the symbolic hub of the protest movement after it began in February. Riot police used buses to block roads and flooded streets with tear gas to drive back the marchers before dawn.

Hours later, mourners gathered in a Shiite village in another part of Bahrain for a 14-year-old boy they claim was killed by security forces. Clashes flared until early Thursday across the oil hub area of Sitra.

"Don’t give up," chanted some of the men. "More protests."

Bahrain remains the outlier of the Arab revolts.

Its Sunni rulers have managed to hold their ground — and even tighten their grip with military help from neighboring Saudi Arabia — against majority Shiites demanding a greater political voice. Washington and Western allies have denounced the punishing crackdowns, but been mild when it comes to Bahrain’s ruling dynasty. The possible risks from a harder line appear too great. They include jeopardizing key Arab military relationships on Iran’s doorstep.

Washington’s Gulf Arab allies argue any gains for Bahrain’s Shiites could open the door for influence by Iran’s Shiite regime.

Bahrain’s Shiite leaders strongly deny any links to Iran. They note that their fight for greater rights goes back decades — and is now re-energized by the pro-democracy wave across the Arab world.

In July, the Shiite political bloc walked out of government-led reconciliation talks, claiming they failed to address key demands such as ending the monarchy’s ability to hand-pick the government. Shiites also appear ready to boycott parliament elections on Sept. 24 — an act that state media has called treason.

Shiites account for about 70 percent of Bahrain’s 525,000 citizens, but claim they face systematic discrimination such as being barred from top political and security posts. Last week, Bahrain’s most senior Shiite cleric, Sheik Isa Qassim, told worshippers that the country’s rulers can either embrace reforms or risk the same fate as Libya’s Moammar Gadhafi.

"Can’t they learn from the fall of dictatorships and see what happens to those who denied their people basic rights?" Qassim said as police helicopters patrolled over his mosque. "We now see what happens to the Libyan dictator, just as what happened to Tunisian and Egyptian despots."

At least 32 people have been killed since the protests began more than six months ago. Activists claim Ali Jawad Ahmad, the 14-year-old buried Wednesday, should be added to the tally.

Opposition groups, including the Bahrain Youth Society for Human Rights, cited witnesses saying the boy died after being hit by a tear gas canister fired at close range by police during the demonstration in the oil hub of Sitra, which has been a hotbed of Shiite protests.

A statement by the Interior Ministry said an investigation was ordered and officials posted a 10,000 dinar ($26,600) reward for information leading to a definitive finding on the death.

The official Bahrain News Agency said an autopsy showed a "neck injury" was the cause of death, and "fractures in that area causing bleeding around the spinal cord." The report added that the boy had bruises on his chin, face, right hand, pelvic area and knees.

Isa Hassan, an uncle of the dead teen, claimed police overreacted when confronted by a small group of protesters after morning prayers marking the end of the holy month of Ramadan. Hassan said the tear gas was fired from about 21 feet (seven meters) away directly at the protesters.

"They are supposed to lob the canisters of gas, not shoot them at people," he said at a memorial gathering for the boy. "Police used it as a weapon."

The death is almost certain to bring more protesters onto the streets.

Until nearly sunrise Wednesday, groups of demonstrators tried to break through police lines to reclaim control of Pearl Square, a main crossroads that was once a protest encampment modeled after Cairo’s Tahrir Square. Some streets in Manama were scenes of running battles.

Police unleashed huge clouds of tear gas to drive back protesters, who in turn created large oil slicks and left makeshift traps such as nail-studded boards to try to slow the riot units. Some protesters manned ambush points to pelt police with stones.

In Geneva, the spokesman for U.N. High Commissioner for Human Rights urged Bahraini authorities to account for all those arrested since temporary martial law-style rule was imposed March 15. It was lifted June 1.

"We are concerned that most of the defendants in these cases may be prisoners of conscience, detained only for exercising their rights to freedom of expression and association," Rupert Colville said. "All such detainees must be released."