A bomb exploded on a railway track in Russia's Dagestan province on Sunday, derailing a freight train days after suicide bombers killed 12 people in the region, Russian news agencies reported. Nobody was hurt.
The pre-dawn blast on a line leading from Moscow to the ex-Soviet republic of Azerbaijan caused eight carriages of a train carrying construction materials to derail, ITAR-Tass and Interfax reported, citing police and emergency officials.
Russia is on edge after suicide attacks in Moscow and Dagestan killed more than 50 people in the past week.
Security was tight as President Dmitry Medvedev and Prime Minister Vladimir Putin attended an overnight ceremony on Russian Orthodox Easter - the most important holiday for the country's dominant religion.
On Wednesday, two suicide bombings in the Dagestani town of Kizlyar killed 12 people including nine police officers, authorties said.
That attack came two days after twin suicide bombings in Moscow's metro killed at least 40 and stoked fears of a major campaign of attacks in Russia's heartland by militant based in the heavily Muslim North Caucasus, which includes Dagestan.