Washington ( CNN ) -- A U.S. military supply ship fired at a small boat in the Persian Gulf on Monday after it came too close , killing one person onboard and wounding three , Defense Department officials said . The USNS Rappahannock , a fuel resupply ship , fired on what two U.S. officials called a `` small , white pleasure craft '' 10 miles ( 16 kilometers ) from the Dubai port of Jebel Ali . The casualties were Indian fishermen , according to the United Arab Emirates ' news agency WAM . U.S. officials expressed their condolences and said the incident is under investigation . The small boat appeared to be headed for that port , the Defense Department officials said , adding that their information was preliminary . The U.S. ship verbally warned the smaller boat when it was 1,200 yards ( 1,100 meters ) away and fired at least one warning shot before the decision was made to fire shots to disable the boat , the officials said . `` In accordance with Navy force protection procedures , the sailors on the USNS Rappahannock ... used a series of nonlethal , preplanned responses to warn the vessel before resorting to lethal force , '' the Navy said in a statement . `` The U.S. crew repeatedly attempted to warn the vessel 's operators to turn away from their deliberate approach . When those efforts failed to deter the approaching vessel , the security team on the Rappahannock fired rounds from a .50-caliber machine gun . '' Officials described the course of events as standard procedures when a small boat gets too close to a U.S. Navy ship . The officials , who would not be identified because of the sensitivity of the situation , also described the small boat as having made a series of maneuvers , but emphasized they were waiting for more details about what exactly happened . UAE authorities are investigating the incident , WAM quoted Tariq Ahmed Al Haidan , a Foreign Ministry official , as saying . And a UAE source said the Emirates ' government would follow up after a review . Jebel Ali is 22 miles ( 35 kilometers ) southwest of Dubai and 37 miles ( 60 kilometers ) north of Abu Dhabi . With 67 berths and extensive dry-dock facilities , it is the largest man-made port in the world and the largest port in the Gulf region and in the Middle East .
NEW : The UAE says the dead and wounded were Indian fishermen . One person appears to have been killed , U.S. officials say . The boat approached too near the USNS Rappahannock , the officials say . The shots were intended to disable the boat , they say .