Demonstrators have blocked roads to a main port in northern Oman and looted a nearby supermarket as protests demanding more jobs and political reform spread to the sultanate's capital.
A doctor said six people had been killed in clashes between stone-throwing protesters and police on Sunday in the northern industrial town of Sohar.
Oman's health minister said one person had been killed and 20 wounded.
Hundreds of protesters blocked access to an industrial area that includes the port, a refinery and aluminium factory.
A port spokeswoman said exports of refined oil products of about 160,000 barrels per day (bpd) from the port were unaffected.
"We want to see the benefit of our oil wealth distributed evenly," one protester yelled over a loudhailer near the port. "We want to see a scale-down of expatriates in Oman so more jobs can be created for Omanis."
Peaceful protests spread to other cities, with hundreds gathering outside a state complex in the capital Muscat and elsewhere.
The unrest in Sohar, Oman's main industrial centre, was a rare outbreak of discontent in the normally sleepy sultanate ruled by Sultan Qaboos bin Said for four decades, and follows a wave of pro-democracy protests across the Arab world.
The sultan, trying to calm tensions, on Sunday promised 50,000 jobs, unemployment benefits of $390 (£242) a month and to study widening the power of a quasi-parliamentary advisory council.
While hundreds of demonstrators blocked roads near the port, hundreds more were at the main Globe Roundabout, angry after police opened fire on Sunday at protesters.
Police fired tear gas as around 200 protesters near a police building, which demonstrators had set fire to a day earlier.
Graffiti scrawled on a statue said: "The people are hungry". Another message read: "No to oppression of the people".
City A.M. Reporter