KIEV, Ukraine - Ukraine's pro-Russian prime minister and his reformist challenger were neck and neck in Ukrainian presidential elections, setting up a runoff vote, election officials said Monday. Foreign observers from NATO and Europe said the vote did not meet European standards for democracy.

The observers found state media bias in favor of Prime Minister Viktor Yanukovich and state interference, including obstruction of opposition activities, said the joint mission, representing the Organization for Security and Cooperation in Europe, the Council of Europe and NATO.

"With a heavy heart, we have to conclude that this election did not meet a considerable number of OSCE, Council of Europe and other European standards for democratic elections," one of the lead observers, Bruce George, said in a statement.

With 94.4 percent of the precincts counted, Yanukovych had 40.1 percent and challenger Viktor Yushchenko had 39.1 percent, the Election Commission said. The results, described as preliminary, made it impossible for either candidate to reach the 50-percent majority needed for a first-round victory. A runoff would be held Nov. 21.