Hillary Clinton, US secretary of state, has warned against the use of “coercion, intimidation and threats” in the resource-rich disputed South China Sea, in pointed comments aimed at Beijing before meetings there with leaders.

China claims sovereignty over almost the entire South China Sea and, after investing heavily in its naval capacity, has become more assertive in recent years. This has increased tension in one of Asia’s biggest potential military flashpoints and exacerbated nervousness in Washington about Beijing’s rise.

As part of its renewed strategic focus on Asia, the Obama administration has been trying to find a difficult balance between putting pressure on China to use diplomacy to resolve regional maritime disputes while remaining neutral on specific claims.