Frank Press, who was a key voice in American science policy as chief science adviser to President Jimmy Carter and then as president of the National Academy of Sciences, promoting international cooperation at a time when Cold War tensions still predominated, died on Wednesday in Chapel Hill, N.C., where he lived in a retirement community. He was 95.

His son, William H. Press, announced the death.

Dr. Press, a geophysicist by training, was a professor at the California Institute of Technology in 1956 when he began consulting for the federal government — first for the Navy, then the United States Geological Survey, the State Department, the Department of Defense and the National Aeronautics and Space Administration, among other agencies.

President Carter named him director of the Office of Science and Technology Policy in 1977. In that role he was the president’s top science adviser, concerned with ensuring that the United States stayed at the forefront of scientific research and with pursuing international alliances and agreements. He had previously worked on a nuclear test-ban treaty with the Soviet Union.

“Cooperation among scientific communities in all countries will become even more important in the years ahead as the problems we face increasingly will transcend national boundaries,” he prophetically told a dignitary-filled banquet in Beijing in July 1978, at the end of a visit to China aimed at breaking down barriers.