QUITO, Ecuador -- Ecuador's Geophysics Institute is reporting that the Tungurahua volcano has erupted three times, spewing ash and lava in what it called an important increase in activity.

The institute said that two moderate explosions on Saturday were followed by a third of greater size, and pyroclastic flow stretched 500 metres down its flank. The blasts created a 8-kilometre column of ash above the volcano, which is located 135 kilometres southeast of the capital, Quito.

Authorities said the lava reached the lower part of a ravine called Achupashal, blocking a route to a tourist site called Banos.

Tungurahua is 5,023 metres high and has been active since 1999. An outburst in 2006 left four dead and two missing.