"It remains our belief at this stage that warning measures were undertaken before shots were fired in this incident," Department of Defense Press Secretary George Little told reporters on Thursday.
"The incident remains under investigation, and we need to await the outcome of that investigation before reaching a final conclusion," he said, adding officials from the Naval Criminal Investigative Service were participating in the inquiry.
When the boat did not respond to the warning attempts, according to the Navy, the Rappahannock fired .50-caliber machine gun rounds at the vessel.
The incident ended with one Indian fisherman injured and one killed. Little could not confirm reports that New Delhi was seeking compensation for the family of the slain fisherman.
“In accordance with Navy force protection procedures, the sailors on the USNS Rappahannock used a series of non-lethal, preplanned responses to warn the vessel before resorting to lethal force,” the Navy said.
“The U.S. crew repeatedly attempted to warn the vessel's operators to turn away from their deliberate approach," according to the service statement.
But recent news reports claim the crew of the Rappahannock fired on the small fishing vessel without warning, prompting Indian officials to call for a full investigation into the incident.
“There are many versions of the incident. We have to wait for the details to emerge.” M.K. Lokesh, the Indian ambassador to the United Arab Emirates, said according to Indian media outlets.
“According to the survivors, there were no warnings given to them," Lokesh said at the time.