U.S. Secretary of State John Kerry mentioned both the possibility of a peace treaty and stronger sanctions against North Korea during a visit to Hiroshima on Monday.

Kerry spoke highly of China’s support for UN Security Council Resolution 2270, which contributed to strengthening the sanctions against the North.

“It is still possible that we will ratchet up even more depending on the actions of the DPRK,” Kerry told journalists, adding that “we are prepared to negotiate a peace treaty on the peninsula.”

Experts said the remark was aimed at China, a necessary partner for the U.S. and South Korea to maintain the