U.S. Secretary of State John Kerry. Pic: AP.

WASHINGTON (AP) — Secretary of State John Kerry says the U.S. is deeply concerned about “aggressive” Chinese action in the South China Sea.

China and Vietnam have been engaged in a tense standoff since China positioned an oil rig in disputed waters last week. Both sides have accused the other of ramming ships.

Kerry said the U.S. wants to see the dispute resolved peacefully, such as through the international law of the sea and arbitration, but not through “direct confrontation and aggressive action.”

Kerry was speaking alongside the foreign minister of Singapore, K. Shanmugam.

Shanmugam echoed Kerry’s desire for Southeast Asian nations and China to agree on a code of conduct for the South China Sea.