The United States warned the government not to purchase the Senkaku Islands last fall, former U.S. Assistant Secretary for East Asian and Pacific Affairs Kurt Campbell said in an interview Monday.

The Japanese government consulted with the State Department prior to the purchase, Campbell revealed, and was given "very strong advice not to go in this direction."

The U.S. government, in urging Japan not to follow through with the purchase, stressed the action could "trigger a crisis" with China, which claims the islands for itself.

"Even though we warned Japan, Japan decided to go in a different direction, and they thought they had gained the support of China, or some did, which we were certain that they had not," Campbell said.

The central government purchased three of the five islets from their private owner in September to bring them under its control. The action enraged the government in Beijing and sparked a wave of anti-Japanese protests across China.

Campbell, while reiterating that the United States takes no position on the disputed territory, stressed that Washington wants to see "effective, positive diplomacy" between China and Japan.

The U.S. wants circumstances in which "both countries appreciate . . . the cockpit of the global economy is in Northeast Asia, and they must get along better," he added.

In connection with Campbell's comments, a Japanese government source said Japan was asked by the U.S. government to be "careful" in handling the matter.

The source also pointed to the possibility that there was a "gap in perception" between Japan and the United States over the purchase of the islands.