BUCHAREST (Reuters) - An explosion killed four people and injured five more at a gas pipeline on a motorway construction site in the eastern Romanian county of Vrancea early on Thursday, a government emergency response unit said.

The fire has since been extinguished and the injured were taken to the hospital. Investigators are looking into the causes of the explosion.

Last month, dozens of people were injured after explosions at a liquefied petroleum gas station in the Romanian town of Crevedia near the capital Bucharest, one of a number of fires that have regularly broken out in Romania.

(Reporting by Luiza Ilie; Editing by Mark Potter)