"Saudi Arabia is not immune to the Arab Spring," Christoph Wilcke, senior Middle East researcher at Human Rights Watch, said in a statement Friday from Beirut.
The rights organization said reformists had several protests this month despite a March ban on demonstrations. Authorities have arrested scores of people engaged in a silent protest in Riyadh to demonstrate against the detention of cleric Yusuf al-Ahmad, jailed in July for expressed solidarity with detainees.
"In 2011, the Saudi government shed all pretense of reform and become the kingdom of silence," Wilcke said.
The criticism follows an announcement from the U.S. government of the sale of nearly $30 billion in F-15 fighter jets to the Saudi government.
"The United States is firmly committed to the security of the Kingdom of Saudi Arabia, as we have been for nearly seven decades," said James Miller, principal deputy under secretary of defense for policy.
Earlier this month, Amnesty International published a 71-page report detailing a "new wave of repression" in the Saudi kingdom since the start of the Arab Spring this year.
Amnesty International says the crackdown is related to a "secret draft anti-terror law" in Saudi Arabia that equates peaceful dissent to terrorism.