More than 200,000 people in the Russian republic of Dagestan have been left without gas supplies after a bomb attack on a gas pipeline.
The explosion destroyed part of the pipeline late on Tuesday, and it was expected to take up to 48 hours to restore supplies.
Dagestan is facing a growing insurgency and has suffered numerous attacks on its infrastructure and security forces.
Last week a suicide bomber killed six policemen in the republic.
Tuesday's blast hit the Mozdok-Kazimagomed pipeline and knocked out supplies to the major town of Derbent as well as surrounding districts, officials said.
President Dmitry Medvedev says the violence in the North Caucasus is Russia's biggest domestic problem.
While in the last few years Chechnya has been more peaceful, the republics of Dagestan and Ingushetia have seen a violent Islamist insurgency spread.