MUSCAT, Oman -- Oman's ruler replaced three top government officials Saturday, a second major shakeup that was celebrated by some protesters but failed to quell more than a week of widening demonstrations calling for jobs and political reforms in this strategically important nation.

The shakeup included the head of the Palace Office, which oversees security affairs, in an apparent attempt to ease calls to hold officials accountable for the killing of a protester last week. Also replaced was a minister who holds the most senior adviser post and another who deals with internal matters within the ruling structure.

The measures failed to halt sit-ins in the capital, Muscat, and the northern industrial city of Sohar, where the unrest began, but they were welcomed by many protesters.

"It was as if a black cloud has lifted. Long live the sultan, long live Oman," said Saeed Hamad, a protester outside the Sultanate's Shura council.

It was the second top-level shakeup that Sultan Qaboos bin Said has ordered in the tightly controlled Arabian peninsula nation. Last week, he replaced six other Cabinet ministers. He later promised 50,000 new civil service jobs and offered a monthly stipend of $390 for job seekers.

Oman, ruled by a powerful family dynasty, is the latest Arab nation to be swept up in a wave of turmoil that has already brought down two leaders and threatened the rule of others.

Oman's unrest remains small compared with Gulf neighbor Bahrain, 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.

Groups of protesters are staging sit-ins around the country to press for economic reforms and investigations to hold officials accountable for attacks on demonstrators. Oil workers in southern Oman were the latest to join the protests.

Police killed one protester in the port town of Sohar, about 120 miles northwest of Muscat, on Feb. 27 after demonstrations turned violent.

In Haima, a key oil region about 300 miles southwest of the capital, oil workers staged a work stoppage to demand more state investments in the area, government officials said. The workers met with a senior envoy from the Oil Ministry.

The officials spoke on condition of anonymity because they were not authorized to talk to the media.

Oman 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.