Seoul, South Korea (CNN) – The US, Australian and South Korean navies are conducting joint exercises off South Korea intended to simulate the interception of shipments of nuclear material meant for North Korea.

The drills, held Monday and Tuesday off South Korea’s Jeju Island, come as US President Donald Trump visits the region for talks which are expected to be dominated by discussion of North Korea. Pyongyang is regularly angered by co-ordinated drills in the region, which it sees as practice for an invasion, but which the US and its allies say is necessary to counter North Korean aggression. These ones are likely to be no different.