HONG KONG  China’s national government tolerates an extensive network of secret jails in Beijing operated by provincial and municipal governments to prevent citizens from complaining to national officials, according to a report released here Thursday by Human Rights Watch.

The report was based on interviews with 38 former detainees who had gone to Beijing to complain about what they described as corruption or other abuses of power at lower levels of government. It said that guards at the “black jails” beat, sexually abused, intimidated and robbed men, women and teenagers.

Provincial and municipal officials in China are subject to a national civil service system that penalizes them based on the number of complaints received in Beijing about their management. So local and provincial officials have a strong incentive to prevent petitioners from reaching the central government.

Sophie Richardson, the advocacy director for Asia at Human Rights Watch, said that abuses were widespread in China’s prison system, which has some judicial supervision, but that they were worse in unofficial jails.