COOK INLET -- Increased earthquake activity has prompted scientists to raise the alert level for Iliamna Volcano on lower Cook Inlet.

The Alaska Volcano Observatory on Friday elevated the alert status for the volcano, about 135 miles southwest of Anchorage.

Officials in a release say earthquake activity has been increasing at the volcano over the last three months and is above background level.

While a significant change, they say, it's not certain if the earthquake activity is because of magma movement.

This doesn't mean an eruption is imminent; it could be similar to earthquake activity from September 1996 to February 1997 that didn't result in an eruption.

The observatory this week said a small eruption occurred at Cleveland Volcano, located about 940 miles southwest of Anchorage.