One of China’s top military leaders took a harsh line on regional territorial disputes, telling an international naval gathering in northeastern China on Monday that the country would strike back with force if its interests came under threat.

The 19th biennial meeting of the Western Pacific Naval Symposium opened in the port city of Qingdao, where China’s northern naval force is based, providing a vivid backdrop to China’s massive military expansion over the past two decades that has seen it build or refurbish three aircraft carriers.