Emergency officials in Costa Rica say they have moved some residents away from the Turrialba volcano outside the capital San Jose after it spewed toxic gas and ash, signs of a potentially imminent eruption.

Costa Rica's National Emergency Commission said its volcano warning level was at green on Wednesday, the lowest of three warning levels, but that it had alerted residents about the possibility of an evacuation from San Jose.

Some villagers were moved away from the populated areas closest to the volcano so they would not be harmed by erupting gases.

The Turrialba volcano located about 65km outside San Jose began a series of eruptions in 2007. Several nearby villages were evacuated and a surrounding national park closed in 2010 when Turrialba last erupted.

Source: Agencies