The head of the U.S. delegation to an upcoming meeting of the International Whaling Commission urged Japan on Wednesday to abandon its plan to expand its so-called research whaling program, indicating that Tokyo could face sanctions over the issue.

"We are surprised, very disappointed," U.S. IWC Commissioner Rolland Schmitten said in an interview with Kyodo News. "We did not believe that there is a scientific foundation behind Japan's current program, let alone expanded program.

"We will consider whatever we have to do to stop this program," if Japan fails to drop its plans via negotiations, Schmitten said prior to the annual IWC meeting in Shimonoseki, Yamaguchi Prefecture.

The meeting will run from April 25 to May 24.