"Admiral Willard reaffirmed the support of the United States to Sri Lanka in defending against terrorist activity through cooperation on maritime security," it said.
"He noted that improvements in human rights protection could lead to enhanced cooperation."
Sri Lanka has come under criticism from human rights groups for alleged abuses by its armed forces in its campaign against the Tigers.
The government denies it condones human rights abuses and says it is investigations the allegations.
Admiral Willard's visit was part of a regional trip to south Asia to meet with his naval counterparts.
He reviewed ongoing maritime cooperation, including naval training and exchanges, between the United States and Sri Lanka.
In Colombo, he met with senior military officials and call