Kiev - The UN warned Friday of an "alarming deterioration" of human rights in eastern Ukraine, where the government is battling an insurgency by armed pro-Russian separatists.
In a new report, UN High Commissioner for Human Rights Navi Pillay also voiced deep concern about "serious problems" of harassment and intimidation facing the Tatar community in Crimea, which was annexed by Russia in March in the face of international outrage.
The report catalogues a litany of "targeted killings, torture and beatings, abductions, intimidation and some cases of sexual harassment" which it said was carried out by anti-government groups in the east of Ukraine.
In a veiled reference to Russia, Pillay called on "those with influence on the armed groups responsible for much of the violence in eastern Ukraine to do their utmost to rein in these men who seem bent on tearing the country apart".
Moscow denounces report
The West has repeatedly warned Russia about the situation in the east, threatening further sanctions if Moscow or its "proxies" disrupt the election.
Moscow swiftly denounced the findings of the report, which was issued just days before a 25 May presidential election in Ukraine the West sees as crucial for the country's survival.
"The complete lack of objectivity, blatant discrepancies and double standards leave no doubts that (the reports) authors were performing a political put-up job aimed at clearing the name of the self-declared authorities in Kiev," the foreign ministry said in a statement.
Kiev's interim leaders have for a month been waging a military offensive against the separatists who took up arms against the central government after the ouster of the Kremlin-backed president in February.
Moscow, which routinely refers to the Kiev offensive as a "reprisal" raid, accused the UN report of "suppressing information about civilian casualties and trying to lay the blame for human rights violations on 'pro-Russian forces'".
Ivan Simonovic, the UN assistant secretary general for human rights who presented the report in Kiev, said the global body had also received a long Russian list of violations allegedly committed by the Ukrainian side.
"We pay extreme attention to all allegations," said Simonovic.'Worrying' rise in abductions
Fighting rages almost every night, particularly around the rebel flashpoint of Slavyansk, and dozens of people have been killed since Kiev launched what it called its "anti-terrorist operation" in mid-April.
In the east, the UN report said there has been a "worrying" rise in abductions and unlawful detention of journalists, activists, local politicians, representatives of international organisations and members of the military.
It said while some people have been released, the bodies of others have been dumped in rivers or other areas and some remain unaccounted for, particularly in the Slavyansk area.
Another 83 people are also still missing after the original pro-EU protests which erupted in Kiev in November last year, with dozens killed in several days of bloodshed.
The report highlighted concerns about the deteriorating climate for the media operating in the east, where rebels have proclaimed independence in two regions following weekend referendums branded illegal by Kiev and the West.
In Crimea, the report said the annexation of the Black Sea peninsula by Russia in March following a similar independence vote was causing problems for many residents, particularly the ethnic Tatar community.
It listed cases of physical harassment and intimidation, restrictions on media and fears of religious persecution among practising Muslims in Crimea.
The annexation of the territory - considered illegal under international law - is "creating difficulties" for Crimean residents, including the halting of an HIV/AIDS programme, the difference in Ukrainian and Russian laws and thorny citizenship issues.
More than 7 200 people from Crimea - mostly Tatars - have become internally displaced in Ukraine, it added.