ANCHORAGE, Alaska (AP) — After being slowed and at times stalled by ice in the Bering Sea, a Coast Guard icebreaker and a Russian tanker were making “great progress” toward Nome on Tuesday, according to an official for the corporation arranging the fuel shipment to the iced-in city.

But the delivery remains challenging, said Jason Evans, chairman of Sitnasuak Native Corp.

“I think there continues to be a lot of pressure on the ice, so when they break the ice it wants to immediately squeeze together, or the broken ice wants to shoot back into the hole they just made,” Evans said.

If successful, the shipment would mark the first time petroleum products have been delivered by sea to a Western Alaska community in winter.

Coast Guard spokesman David Mosley said the tanker Renda and the icebreaker Healy were less than 100 miles from Nome Tuesday afternoon, having made it through 53 miles of ice-covered waters Monday.

The icebreaker is creating a path for the tanker through ice that is between 2 and 3 feet thick, Mosley said. The progress the vessels are making — compared with earlier reports that they were slowed and sometimes stopped with ice pinching the sides of the tanker — has to do with day-today changes in the ice, he said.