DUBAI, United Arab Emirates — Saudi Arabia’s human rights conduct came under withering criticism by a New York-based rights watchdog, which documented unfair trials, detention of children, and oppression of women and foreign laborers.

Human Rights Watch released its report Saturday after being invited by Saudi authorities to conduct a four-week mission to the kingdom starting in December.

The rights group said its 13-person team, led by executive director Kenneth Roth, operated under 24-hour surveillance and was blocked at times from observing trials and visiting jails. But Saudi leaders also showed a “newfound openness” toward human rights, and the group said it gained unprecedented access to senior officials among the judiciary, police, and enforcers of Islamic law.

“By restricting our access to prisons and withholding general permission to observe trials … the Saudi government gave the appearance that it still has much to hide,” said Sarah Leah Whitson, Middle East and North Africa director at Human Rights Watch.

Attempts to reach the Saudi Information Ministry on Sunday were unsuccessful.

A Saudi journalist and a human-rights activist lauded what they described as long-overdue criticism of police and court authorities who, they allege, have evaded government attempts to curb their power and misuse Islam to subject women, children, prisoners, and foreigners to abuses that have no basis in law.

“Ours is not an open culture. It is a culture of hiding,” said Somayya Jabarti, an editor at Jiddah-based newspaper Arab News said Sunday. “To solve these problems, they need to be brought into the open.”

“The problem isn’t with the leadership, it’s the authorities between the leadership and the people,” Ms. Jabarti said.

A Saudi human-rights activist, who spoke on condition of anonymity because of the sensitivity of the issue, also said the country remains plagued by extremists who dominate midlevel positions in the police and judiciary.

King Abdullah, who took the throne in 2005, has paved the way for a more open discussion of human rights issues, the Saudi activist said, but hard-liners have derailed reforms and little has changed.

“Yes, the leadership is more receptive now. But the leadership should have the political will to stop this,” he said. “There is just this madness and neglect and indifference.”

Many of the abuses cited in the Human Rights Watch report receive little attention in the regional new outlets. The report documented thousands of prisoners jailed under conditions similar to those at the American military camp in Guantanamo Bay, Cuba. Saudi secret police hold political prisoners and those suspected of ties to the Iraq insurgency for years without charge or trial, the report alleged.