ASSOCIATED PRESS

The Llaima volcano, one of Chile's most active, erupted again on Saturday, sending a stream of lava down its slope and spewing a long plume of ash, authorities said.

At the same time, the Chaitén volcano rumbled once again and could be preparing for another eruption, according to a Chilean volcanologist.

Recent seismic activity and ash emissions from Chaitén could lead to the ''worst-case scenario'' for reactivation, said Jorge Muñoz of Chile's geological service.

The Chaitén volcano, located 745 miles south of Santiago, began erupting May 2, emitting clouds of ash and rock that forced the evacuation of thousands around the town of Chaitén. Residents have yet to return.

Its activity had declined since then, but vulcanologists began seeing renewed activity Wednesday, and Muñoz warned Saturday of a new eruption in the coming days.

The Llaima volcano, 400 miles south of Santiago, registered a number of explosions ''at the crater level,'' the government's Emergency Bureau said, and a slow stream of lava some 250 yards long was seen on its slopes. It also spewed a plume of ash 7,000 yards into the air.

A state of alert was issued for small villages near the 9,400-foot volcano, which has had 38 large eruptions since 1640.

It erupted twice earlier this month.