A Russian passenger boat with more than 180 people on board has sunk in the Volga river, killing at least one person and leaving nearly 100 others missing.

The Itar-Tass news agency quotes an Emergency Situations Ministry spokeswoman as saying 84 people had been rescued Sunday, and that emergency operations 750 kilometers east of Moscow, in the republic of Tatarstan, were continuing. The ministry said an unknown number of passengers were thought to have paddled ashore - a distance of 3 kilometers - on improvised rafts.

The Volga, Europe's largest river, is a popular tourist destination. The Associated Press said the double-decker boat was built in the 1950s and quotes safety officials as saying it lacked many modern-day safety features.