An oil tanker has run aground at a port in Alaska, the US Coast Guard says.
The Seabulk Pride broke free from moorings while being loaded in Nikiski, south-west of Anchorage, and ran aground on silt.
The double-hulled tanker was carrying more than 100,000 barrels of different oil products. The Coast Guard says some oil has leaked into the sea.
An oil spill from the Exxon Valdez in Alaska in 1989 devastated wildlife and took four years to clean up.
A spokesman for the Tesoro refinery, which had chartered the vessel, said the Seabulk Pride broke free after being hit by an ice floe.
Alaskan environmental protection authorities have sent a helicopter and tugboats to the area to assess how much oil has been spilled.
Coast Guard investigators say there appears to be little damage to the vessel.
Thirty-four people were on board at the time of the accident.
The 575-foot long tanker was built in 1998 with two hulls, a design brought in during the 1990s to protect cargoes.
It is owned by Seabulk International Inc, which was recently acquired by Seacor Holdings Inc.