HONOLULU -- Environmentalists are blaming the Navy's RIMPAC exercises for a whale beaching itself on Molokai.

The whale repeatedly "stranded itself" on Molokai Monday, and a veterinarian euthanized the whale in the afternoon, officials said.

The Navy said it would be "speculative" to connect the whale's death to its exercises in the Pacific Ocean this month, but environmental lawyers who have sued the Navy over sonar's effect on whales in the past said the Navy's response is a "disgrace."

The 2,500-pound whale went ashore at Kawela Beach, north of Kaunakakai on Molokai, and kept stranding himself even after volunteers pushed him back into the ocean several times.

Scientists said it is a Cuvier's beaked whale that lives in deep water. Now, they are trying to figure out why it beached himself.

"People should understand that whales strand for all sorts of reasons," said Chris Yates of the National Oceanic and Atmospheric Administration Fisheries Division.

A veterinarian administered euthanasia by injection to the whale, and the Coast Guard transported it to Oahu. Scientists from Hawaii Pacific University performed a necropsy on the whale, but they said may never know what caused its death.

"There's so many things that could happen to the animal, that we can't necessarily point to one thing, but if we can rule out a lot of different things, then we can at least narrow it down," HPU professor Brenda Jensen said.

The death happened during the Rim of the Pacific military exercises, when 35 naval ships from 10 countries hold exercises in waters around Hawaii.

Paul Achitoff of EarthJustice sued the Navy, saying it failed to properly protect whales from sonar.

"When one does strand at the same time that the Navy is using their sonar, you certainly have to wonder if there's a connection, and there's a good possibility that there is," Achitoff said.

A spokesman for the U.S. Navy's Pacific Fleet said, "There's no indication that Naval activities, RIMPAC or otherwise, caused or contributed to the whale's stranding."

Achitoff said the type of whale that stranded itself is the one most frequently hurt or killed by Navy sonar.

"Eighty-five percent of all of the whales that have been found stranded as a result of the Navy's sonar have been Cuvier's beaked whales," Achitoff said.

Since January 2007, the Navy has agreed to power down its sonar if spotters see a whale within 1,000 feet of a Navy ship.

Earlier this year, a federal judge in Honolulu ordered the Navy to take additional measures to reduce the risk of harm to marine mammals, but the order did not specifically apply to the RIMPAC exercises, which end Wednesday.