ANCHORAGE, Alaska - Alaska environmental regulators say they still don't know the source of the oil that recently contaminated two seals and five birds near Gambell on St. Lawrence Island.

The state Department of Environmental Conservation says officials also are trying to determine if the same oil source contaminated a spotted seal in early September near Shishmaref about 230 miles to the northeast.

The DEC says analyzed oil samples from a spotted seal killed by a subsistence hunter on St. Lawrence Island in late October hunter indicate a "heavier" petroleum product. Samples of a brown substance on a ringed seal hunted outside of Gambell Monday also will be analyzed.

Four common murres and a crested auklet also have been seen with oil. One of the murres was sent to Anchorage for rehabilitation.