Yakin Erturk, UN special rapporteur on violence against women, spoke out on the issue after a recent visit to the republic.
"I heard first-hand accounts of women being arbitrarily detained and tortured following targeted operations [by the Russian special forces]," she said.
"This is said to be in response to women's involvement in terrorist attacks, particularly as suicide bombers."
Two women were among a team that seized a school in North Ossetia in September resulting in 344 deaths, and many bombings over the past few years have been committed by so-called black widows seeking to avenge their dead husbands, sons or brothers.
"In the absence of the rule of law, the civilian population suffers abuse by security forces and Chechen armed groups, leaving a climate of fear and insecurity," Erturk said.
After the first armed conflict in Chechnya in 1994-1996, Moscow again poured troops into the rebellious republic in October 1999, quickly getting mired in a brutal guerrilla confrontation with various rebel leaders.
Meanwhile, a communique issued from UN headquarters in Geneva quoted Erturk as calling on Russia to ensure that laws and practices aimed at curbing "terrorism" conform to international human rights norms.
"In the absence of the rule of law, the civilian population suffers abuse by security forces and Chechen armed groups, leaving a climate of fear and insecurity"
UN Special Rapporteur on Violence against Women
Erturk was reporting on a fact-finding mission during which she collected evidence from victims of human-rights violations, including relatives of missing persons and displaced persons in Chechnya and Ingushetia.
On the general theme of treatment of women in Russia, the UN official's report also called on the Russian government to protect women better from domestic violence.
The overall situation of Russian women has improved over the past decade, she said, noting that the Russian Federation had undertaken administrative and legislative changes contributing to improving matters.
Violence against women and sexual discrimination nevertheless remain only secondary themes on the political agenda.
Russia has been condemned for
widespread abuses in Chechnya
A bill on domestic violence submitted to the Duma (lower house) has not been passed, and a women's commission set up to promote sex equality in public policy and programmes was abolished this year.
Violence, particularly domestic violence, continues to cause damage and threaten the lives of thousands of women every year, Etruk said.
Because of lack of resources, many women were forced to continue sharing an apartment with a violent partner even after a divorce.