Washington: Insisting that the US naval ship had forewarned the Indian fishermen before opening fire, the Pentagon on Thursday said that the incident remains under investigation and one should wait for the outcome of the probe before reaching any conclusions.

"We would be pleased to update our Indian counterparts as we learn more through the investigation," Pentagon Press Secretary George Little told reporters at a news briefing.

"I would again express regret for the loss of life in this incident. It remains our belief at this stage that warning measures were undertaken before shots were fired in this incident. The incident remains under investigation, and we need to await the outcome of that investigation before reaching final conclusions," he said.

Little was responding to questions on the statement by the Dubai Police Chief that no warning were issued by the US naval ship before it fired shots at the fishing vessel off the coast of UAE resulting in death of one Indian fisherman and injury to three others.

When asked if he had any proof that the US Navy ship issued warning to the fishing vessel, the Pentagon official said the issue is being investigated.

"Very typically in these incidents in the Gulf, there are either audio recordings to the bridge from a security team or there is actual videotaping of these incidents. So can you tell us or can you find out, are there any audio or video recordings that would demonstrate the Navy crew did conduct nonlethal warning measures?" he was asked.

"I do not know," Little said.

"I will take the question. This is under investigation, of course, as I've said and I'm sure that this is the kind of question that the investigators will ask," the Pentagon official said.

"I wouldn't get into specifics. This is under investigation. But we firmly believe at this point that the USS Rappahannock did employ a series of warning measures to alert the oncoming vessel," Little said in response to a question.