About 10 orcas were trapped in drift ice off the eastern coast of Hokkaido on Tuesday but by Wednesday it appeared that they had escaped to safety, local officials told NHK.

The Japan Coast Guard was alerted Tuesday morning by a fisherman who reported seeing an orca approximately 1 kilometer off the coast of the town of Rausu and surrounded by drift ice, the broadcaster reported.

Video footage taken by Seiichiro Tsuchiya, a marine life expert at Wildlife Pro, showed the orcas, which are also known as killer whales, bobbing up and down frantically, trying to get air. Larger whales can spend long periods underwater, but orcas, which are members of the dolphin family, can only stay submerged for several minutes at a time.

Several orcas appeared to be bleeding from their lower jaws, likely a result of injuries sustained in their attempts to escape. There also appeared to be several calves among the animals that were trapped, Tsuchiya told NHK.

Local residents described the orcas as being confined to a small area of open water about 10 square meters in size, where they became caught between two large pieces of ice.

But the orcas disappeared later on, leading local officials on Wednesday to believe that they might have escaped.

Rausu town officials searched for the orcas for about an hour and a half on Wednesday morning but they were nowhere to be seen, according to the NHK report.

According to the town officials, the density of the drift ice seems to be lower than on Tuesday, and hopes are that that may have allowed them to escape.

The sea surrounding eastern Hokkaido typically experiences drifting ice each winter, but recent years have seen a decrease in ice due to rising sea temperatures. However, according to the local meteorological observatory, the ice floes may have grown larger due to a sudden cold snap that began on Monday, obstructing the orcas' path.