The unrest Friday in the northern industrial city of Sohar _ where the protest movement began more than six weeks ago _ suggests that high-level shakeups and other concessions by Oman's rulers still fall short of the demonstrators' demands for greater political freedoms.
In a sign of worries about more violence, military imposed a nighttime curfew in Sohar and stationed units around government offices and other key buildings.
Medical officials said a 22-year-old man died early Saturday from injuries in the clashes and at least four other protesters were wounded. The precise cause of death was not immediately known.
Authorities say they used tear gas, water cannons and rubber bullets in "self defense" after the crowds began pelting riot police with stones and brandishing knives, according to a statement by Oman's prosecutor's office.
Protesters, however, claim that police opened fire with live ammunition.
The medical officials spoke on condition of anonymity because they were not authorized to brief media.
It was the second protest-related death in Oman since unrest broke out in late February to demand more job opportunities and a greater public voice in political affairs in the tightly controlled nation. Oman's ruler, Sultan Qaboos bin Said, has replaced more than a dozen Cabinet officials and promised other reforms such as 50,000 new civil servant posts.
But it has failed to halt the wave of rallies, sit-ins and strikes to pressure for changes that include more media freedoms and weakening the ruling system's grip on power.
Protest leaders urged for more demonstrations in the capital Muscat and other cities around the country.
Oman's unrest remains limited compared with other Arab uprisings, but it is closely watched because of the country's strategic role as co-guardian of the Strait of Hormouz. Oman and Iran share authority over the crucial waterway at the mouth of the Gulf, which is the route for 40 percent of the world's oil tanker traffic.
Oman also plays an important role as a mediator between Iran and the West because of its strong ties to Tehran and Washington. Last year, Oman negotiated a $500,000 bail for the release of American Sarah Shourd from Iranian custody.
Shourd and her two U.S. companions _ who remain jailed in Tehran _ were arrested along the Iran-Iraq border in July 2009 and charged with espionage.