Activists said the recent arrests undermined Prince Mohammed’s efforts to introduce social changes to the kingdom — or, at least, the international image boost they have given him. Along with diversifying the economy, the prince aims to open up what is still a highly traditional society by encouraging concerts and movie theaters, promoting tourism, and granting women more freedoms, such as the right to drive.

“It’s very clear now that the Saudi government hasn’t learned any lessons from the international pressure,” said Yahya Assiri, the director of ALQST, one of the rights groups. “The only thing they’ve learned is that they can avoid international pressure with sports and entertainment and P.R. campaigns.”

The people arrested recently were “not activists, and they haven’t been critical for many years,” he said. “It’s just repression.”

Those arrested over the past 10 days included a female journalist at the newspaper Al Watan, Maha al-Rafidi, who had supported some political prisoners with posts on Twitter, according to Prisoners of Conscience, a rights group that tracks the kingdom. Another, Fouad al-Farhan, an entrepreneur and blogger who had started a business skills training company, had been detained previously for publicly supporting democratic reforms, but he had signed a pledge to stop his activism and was not currently writing about politics, Mr. Assiri said.

In a bid to make peace with the government, some of the others had even publicly come out in favor of Prince Mohammed’s Vision 2030 plan for transforming Saudi Arabia’s economy, Mr. Assiri said. They included the writers Abdulmajeed al-Buluwi and Badr al-Rashed. Sulaiman al-Saikhan al-Nasser, an academic who had been involved in government cultural initiatives, was also targeted, according to Prisoners of Conscience.