Secretary of State Mike Pompeo has been in the Federated States of Micronesia meeting with its president and leaders from Palau and the Marshall Islands.
He said the Compact of Free Association agreements - due to expire in 2024 - are crucial for Washington's Pacific allies.
"They sustain important economic assistance with the people in these countries. They sustain democracy and human rights in the face of Chinese attempts to redraw the Pacific in its authoritarian image.
"Today your citizens in this region of the world can see the Trump administration and its enduring commitment to the Indo-Pacific and our appreciation for the strong friendships here."
Mike Pompeo said the US will continue to assist the freely associated states with natural disasters and tackle other challenges.
He said there had been "thought given" to the possibility of moving the responsibility for the US relationship with its freely associated states from the Interior Department to the State Department. Some critics have said the Interior Department's role is "colonial" because of its otherwise-domestic responsibilities.
The president of the Federated States of Micronesia, David Panuelo - who last week accepted a $US2 million donation from China to the country's trust fund - said a relationship with the US came "first and foremost".
"Our relationship with China is purely on economic and technical cooperation. I want to make that clear ... the US is providing the peace and stability in the region."