Two once-doomed California gray whales splashed with new life Wednesday as a pair of powerful Soviet icebreakers leading a massive rescue effort bashed through the last frozen barrier to their escape to the open sea.

"The whales are ready to get out of there," said Cindy Lowry of Greenpeace as the two Soviet icebreaking ships cracked their way through the wall of ice at the edge of the arctic floe trapping the two young giant mammals.The whales, whose dramatic plight has set off an extravagant international rescue effort in the icy arctic, responded by vigorously swimming around their latest breathing hole.

"They are swimming up and down, really energetic," Lowry said. She said the whales were "so active they were causing waves."

The 20,241-pound Admiral Makarov, an 11-story icebreaker, and the 13,514-ton Vladimir Arseniev, an icebreaking cargo vessel flying an American flag alongside the hammer and sickle of the Soviet Union, began their attack on the icy ridge Tuesday afternoon.

They moved through the ice with such force that Lowry and another Greenpeace member keeping an all-night vigil beside the whales were afraid the huge icebreakers would plow right into them. But the threat turned out to be illusory.

The Soviets battered their way through the ice until 3 a.m. Alaska Daylight Time (5 a.m. MDT), getting within a half-mile to a mile of the whales.

Other rescue teams planned to fire up the 11-ton one-of-a-kind Archimedean screw tractor sometime after the Alaska sunrise to finish clearing a 16-foot-wide path for the whales to a 220-mile channel that will eventually take them to the open sea. The tractor's pontoons are equipped with screw-like ridges that cut through the ice.

The remaining ice was 8 to 18 inches thick and the consensus around the whales' breathing hole was that they would be swimming free by day's end.

The third whale that was with them when they were first discovered Oct. 7 huddled at a breathing hole in the frozen Beaufort Sea 18 miles from Barrow, the northernmost tip of the United States, was presumed drowned.

The Russians provided a sudden surge in a protracted rescue operation that has also involved Eskimos, the Alaska National Guard, scientists, U.S. government experts and environmentalists. Chainsaws, a 7-ton "concrete yo-yo," the Archimedean screw tractor and Jacuzzi-like devices used to keep the water from freezing have been thrown into the fray.

A giant icebreaking barge was one of the first hopes for saving the whales, but it never got close to the site, barely getting out of Prudhoe Bay.

"Let us begin to cut ice," Captain Sergei Reshetov of the Admi ral Makarov declared as the Soviet vessels began their assault.

Rick Skluzacek, who helped keep the whales' breathing holes open with his de-icing machines, said, "I haven't seen them (the whales) look that good since I've been here."

The whales got trapped getting a late start on their southern migration from their summer arctic feeding grounds.

After hours of planning "Operation Breakthrough" with U.S. rescuers, the Russian ships sailed one-behind-the-other through ice-covered water to the ridge,which extends for several miles, leaving a long trail of broken ice behind them.

"In the eastern part of our country," Reshetov said in excellent English, "the ice is very hard."

In another development Tuesday, the Federal Aviation Administration ordered flights around Barrow Point to stay above 2,000 feet because of crowding by small planes taking a look at the whales, The Washington Post said.

"To have these airplanes swarming around like little bees over the rescue operations turns into a nightmare on the ground," Paul Steucke, an FAA spokesman in Anchorage, told the Post. "In addition, it's one heck of a hazard in the sky. The opportunity to hit each other is quite high."

Normally, there are two commercial flights in and out of Barrow each day.