A U.N. employee and his alleged co-conspirators each pleaded not guilty in U.S. District Court in Manhattan yesterday to charges that they engaged in an elaborate immigration fraud scheme.

A U.N. document translator, Vyacheslav Manokhin, and an immigration attorney’s aide, Vladimir Derevianko, were arrested August 6 on charges of helping foreign individuals illegally acquire American entry visas indicating they were attending U.N. conferences. According to the indictment, some of the conferences for which visas were granted were made up and others were not attended by the visa holders.

Mr. Manokhin, 45, and Mr. Derevianko, 44, are charged with conspiracy to commit fraud for allegedly preparing false documents on U.N. letterhead and using Mr. Manokhin’s position at the international body to make it appear as if the United Nations approved the entry visas, the indictment states. Mr. Manokhin allegedly signed the letters using aliases that included “Leonardo Brackett,” and provided his own U.N. telephone number as that of “Mr. Brackett” so that he could answer the calls and pretend to be an assistant for “Mr. Brackett” and vouch for the authenticity of the documents, according to the indictment.

Mr. Derevianko is also charged with one count of making false statements to federal officials, according to the indictment.

The third defendant in the case, Kamiljan Tursunov, 44, allegedly paid $15,000 for his entry visa, and confessed to federal investigators that he did not attend any U.N. conferences and that he moved to Florida upon entering the country in 2005, according to the indictment. He is charged with conspiracy to commit fraud. Messrs. Tursunov and Manokhin each face a maximum of five years in prison, if convicted, and Mr. Derevianko could face 10 years. The men are to return to court October 4.