The Italian foreign minister, Federica Mogherini, suggested on Friday that Russia could avoid further sanctions if it took demonstrable steps to restore stability in Ukraine, including a credible presidential election next weekend and productive negotiations on the country’s Constitution.

“We should concentrate on making the political process work rather than concentrating only on the sanctions,” Ms. Mogherini said at the United Nations headquarters in New York, where she met Friday with Secretary General Ban Ki-moon.

She added that the Organization for Security and Cooperation in Europe was “confident” that its election observers would be able to travel freely throughout the country during the polling on Sunday.

The report, compiled by a 34-member team of human rights monitors in Kiev and four other cities, named only the “Slovyansk self-defense unit” in the eastern city of Donetsk, but it reported several instances of attacks by other pro-Russian activists on rallies in support of Ukrainian unity and against lawlessness. “In most cases, local police did nothing to prevent violence, while in some cases it openly cooperated with the attackers,” the report said.

The United Nations expressed particular concern about increasing abductions and unlawful detentions in eastern Ukraine that appeared to be targeting journalists and to be controlled by the Slovyansk unit, reporting that by May 5 it was aware of 17 unlawful detentions in the Donetsk region alone.

Harassment of journalists and media outlets, and the increasing prevalence of hate speech, threatens freedom of speech and “is further fueling tensions,” the United Nations said. “Both these factors are deepening divisions between communities and exacerbating the crisis.”

The monitors said they also had credible reports that Ukraine’s security service had detained some pro-Russian activists and transferred them to Kiev in circumstances that amounted to enforced abductions.