The letter, dated April 4 and signed by two senior members of the European Parliament (MEPs) on behalf of the European Parliament, describes "an unprecedented and unacceptable incident" involving the OSCE's Office for Democratic Institutions and Human Rights (ODHIR), which monitors elections.
According to the letter, ODIHR's press service urged the head of the European Parliament's delegation to the March 31 election, Polish MEP Dariusz Rosati, to tone down the delegation's contribution to a joint press release by removing wording about "the ongoing Russia-waged war against Ukraine" and replacing it with a reference to "the ongoing conflict in the east."
"Rosati made it clear that he understood the constraints faced by the OSCE...but stressed he would not depart from his original text," the letter said. "He therefore agreed that the European Parliament would not be quoted at all in the joint press release prepared by the ODIHR."
Despite reassurances from ODIHR, it said, copies of a joint press statement with the "unacceptable" watered-down wording were made available throughout the joint press conference by the monitors in Kyiv on April 1 and were "distributed to the numerous journalists present."
The letter was addressed to Ingibjorg Solrun Gisladottir, the director of ODIHR in Warsaw. It was signed by British Labour Party MEP Linda McAvan, who chairs the European Parliament's Development Committee, and German center-right MEP David McAllister, who chairs the Foreign Affairs Committee.
The "issue at stake is extremely serious. It infringes on the right of the European Parliament, as an independent and sovereign international organization, to express its own views on a specific topic," the letter said. It asked ODIHR to provide an explanation ahead of the April 21 runoff vote between incumbent President Petro Poroshenko and comedian Volodymyr Zelenskiy.
Reached by telephone on April 5, ODIHR spokesman Thomas Rymer told RFE/RL the organization would respond directly to the European Parliament, saying that "the proper way is to respond to their concerns directly to them."
"As I understand we've received the letter, and in any case with any partner organization of course we would send a reply and we would...work with them," Rymer said. He did not comment on the substance of the accusation.
Russia seized control of Ukraine's Crimea region in March 2014, after sending in troops and staging a referendum dismissed as illegitimate by at least 100 UN members states.
Moscow also encouraged separatist sentiment across much of Ukraine around that time and backs separatists who hold parts of the Donetsk and Luhansk regions in eastern Ukraine, where the UN says the five-year-old war between the militants and Ukrainian government forces has killed some 13,000 people.
Both Russia and Ukraine are members of the 57-nation OSCE.