A poet and a blogger were among 10 people arrested in Oman in the past two weeks in what one source said was a police crackdown on dissent amid rising discontent in the small US ally sitting near key Gulf shipping routes.
Activists said on Saturday that six people arrested on Friday night included blogger Hassan Rukaishi, authors Hammoud Al Rashedi and Nabhan Al Hanashi and poet Hamad Al Kharusi.
Another four were arrested in separate incidents in the past two weeks, bringing the total to 10, activists said. Local activists wrote on a Facebook page of the Omani Group for Human Rights that three of them were being held by the police's "special section", but gave no further details.
"The arrest campaign affected six people in one go, including authors and bloggers, and without a specific charge, a warrant or a court decision," a Facebook page of the Gulf Discussion Forum, a group of human rights activists in the Gulf region, said.
"The arrests come after the general prosecution threatened to take appropriate legal action against defamatory writings or anyone making incitement calls under the pretext of freedom of expression," the group added.
Officials were not immediately available to comment on the report, which was confirmed by sources in Oman who declined to be identified.
One source said the six arrested on Friday were being investigated on suspicious of "incitement" but gave no further details.
Another said the arrests may have been linked, among other things, to a recent protest in the capital Muscat, where activists had been pictured with signs deemed disrespectful to senior officials.
Protests inspired by Arab Spring uprisings in Tunisia and Egypt erupted in various parts of Oman last year demanding jobs and an end to corruption. Security forces moved against the protests, which ended after promises of reforms. Omani activists say only a handful of the promised reforms has been realised.
Salim Al Tuwayyah, a blogger who also works at a local newspaper, said anger was rising over what people see as the government's failure to deliver on promises for better living conditions.
"There is a lot of worry that this campaign may spread to other activists and bloggers," Tuwayyah said by telephone from Oman.
"There is an urgent need to try to find real solutions to the problems facing the country, raise salaries and put officials suspected of corruption on trial," he added.
A series of labour strikes has gripped the Gulf Arab sultanate, a small oil producer which sits on the strategic Strait of Hormuz where a third of the world's seaborne oil exports pass.
Omani media have reported that workers have walked out in recent weeks in the oil, health and education sectors to press for better pay and living conditions.
Authorities last month detained three activists visiting a desert oil field to document a protest, Omani media reported. The strike was later resolved by the intervention of Oman's consultative Shura Council.
Activists said on Saturday that two of the three - Habiba Al Hinai, a former Omani volleyball player, and lawyer Yaqoub Al Kharusi - had been released. The fate of the third activist, Esmail Al Muqbali, was not immediately known.