KYIV, Ukraine — Ukrainian security officials said Wednesday that they had arrested a Ukrainian woman “red-handed” on suspicion of helping Russian intelligence services, including preparations for an assassination attempt on President Volodymyr Zelensky last month.

“The security service detained an informant of the special services of the Russian Federation, who, on the eve of the recent working trip of the president of Ukraine to the Mykolaiv region, was gathering intelligence about the planned visit,” Ukraine’s State Security Service, the SBU, said in a statement posted on its website.