Group of Seven leaders expressed their concern about tensions between China and a number of other Asian countries over resources in the East and South China Seas and warned against any use of force.
"We are deeply concerned by tensions in the East and South China Sea. We oppose any unilateral attempt by any party to assert its territorial or maritime claims through the use of intimidation, coercion or force," the G7 leaders said in a statement after evening talks in Brussels.
"We call on all parties to clarify and pursue their territorial and maritime claims in accordance with international law."
China claims almost the entire oil- and gas-rich South China Sea, and dismisses competing claims from Taiwan, Brunei, Vietnam, the Philippines and Malaysia. Japan also has a territorial row with China over islands in the East China Sea.
Tensions have surged in recent weeks after China placed an oil rig in waters claimed by Vietnam, and the Philippines said Beijing could be building an airstrip on a disputed island.