GENEVA — The U.N. human rights office said in a report Monday that Russia is violating international law in Crimea, including by imposing Russian citizenship on its people and deliberately transferring hundreds of prisoners and detainees to prisons in Russia.

The report, drawn up under an existing request from Ukraine’s government, chronicles alleged rights violations and abuses in Crimea since Russia annexed the peninsula from Ukraine in 2014. Russia has refused to budge despite international outrage and biting U.S. and European Union sanctions against Moscow.

A Russian diplomat in Geneva insisted that the U.N. rights mission didn’t have competency to examine the situation in Crimea, insisting that the peninsula was part of Russia now.

“It is strange that the human rights mission in Ukraine assesses the situation in the Russian Federation,” the diplomat said on condition of anonymity because any official declaration can only come from Moscow. “This is un-mandated work.”

The report urges Russia to “effectively investigate” alleged torture, abductions and killings in the peninsula, while decrying denials of access to its own team — and urges the international community to support push for that access.

“A key finding of the report is the grave deterioration of respect for human rights and fundamental freedoms in Crimea over the past 3-1/2 years,” said Fiona Frazer, head of the U.N. human rights monitoring mission in Ukraine. She said the transfer of hundreds of prisoners and pre-trial detainees violates international law.

Thousands of Crimean residents who had refused to live under Russian jurisdiction had left for mainland Ukraine, Frazer said, while “tens of thousands more became foreigners, and as a result, faced significant hardship” either because they rejected or did not qualify for Russian citizenship.

“The lack of Russian federation citizenship limited or prevented their access to employment, health care protection, and property and political rights, with serious consequences,” she said.

In a statement, U.N. human rights chief Zeid Ra’ad al-Hussein said the imposition of Russian citizenship can be equated to forcing people to “swear allegiance to a power they may consider as hostile.”

Frazer said other restrictions involved the freedom of peaceful assembly and association, or the ability to register as non-governmental organizations or as media outlets.