MOSCOW (AP) - Russian authorities are ordering an increase in security at train stations and other facilities around the country.
The move comes after a suicide bomber killed 14 people today in an attack on a bus in the southern city of Volgograd. It was the second deadly attack in two days in the city that's just 400 miles from the site of the 2014 Winter Olympics.
Yesterday, 17 people were killed when a suicide bomber attacked a railway station. Russian authorities say they believe the same group carried out both attacks.
The heightened security comes as Russians prepare to celebrate the New Year, the nation's main holiday. In Russia's second largest city, St. Petersburg, the local governor canceled a New Year's fireworks show.
Volgograd, which is northeast of the Olympic city of Sochi, serves as a key transport hub for southern Russia. There are a number of bus routes linking it to Russia's North Caucasus, where insurgents have been seeking an Islamic state.