Marine Corps leaders are asking for more than a year of support to investigate an incident that saw one of its boats sink.
Marine Corps leaders in San Diego on Wednesday asked the Defense Department for $1.8 million to help investigate the April 20 attack.
The U.N. says a Chinese-flagged ship, the Mariana, was trying to intercept an oil tanker headed to a port in the Philippines.
It sank without warning.
The United States says there were no American sailors aboard the Marissa.
The ship had been carrying some 200 marines and one civilian, who was injured.
The Pentagon is looking into the cause of the attack, and the Coast Guard is expected to release a preliminary report next week.