U.S. acted after pirates aimed at ship captain

WASHINGTON (Reuters) - President Barack Obama authorized killing the Somali pirates holding U.S. cargo ship captain Richard Phillips, and a commander acted upon concluding the pirates were about to kill the hostage, a U.S. Navy official said on Sunday.

"They were pointing the AK-47s at the captain," Vice Adm. William Gortney, head of the U.S. Naval Central Command, said in a Pentagon briefing from Bahrain.

Gortney also said Washington had rejected ransom negotiations with the pirates. "The United States government's policy is to not negotiate," he said.

But he said military members had been in hostage talks with the pirate crew, and the talks grew "heated" before the commander on the scene ordered the shots that killed three pirates holding Phillips in a lifeboat.

"If he was not in imminent danger, they were not supposed to take this sort of action, they were supposed to let the negotiation process work it out," Gortney said.

"The on-scene commander took it as the captain was in imminent danger and then made that decision (to kill the pirates), and he had the authorities to make that decision, and he had seconds to make that decision."

"Our authorities came directly from the president. And the number one authority for incidents, if we were going to respond, was if the captain's life was in immediate danger," Gortney said.

The U.S. Justice Department, which is reviewing how to prosecute the lone pirate taken into custody, wants to take him to Kenya, which recently signed a piracy prosecution deal with Washington, Gortney said. It was also possible the pirate could be taken to the United States, he said.

(Reporting by Randall Mikkelsen; Editing by Eric Walsh)