The head of the US military's Pacific Command on Tuesday stressed the importance of diplomacy, rather than a preemptive military strike, to address North Korea's growing nuclear and missile threats.

Tensions rose after the North last month tested two intercontinental ballistic missiles that appeared to bring much of the US within range, with President Donald Trump warning that Washington could rain "fire and fury" on Pyongyang.

The North's leader Kim Jong-Un then threatened to fire a salvo of missiles towards the US Pacific territory of Guam.

He later backed away from the plan, but tens of thousands of South Korean and US troops this week began an annual war game hated by Pyongyang.

To tackle the North's menaces, "the most important starting point is the diplomatic starting point", said Admiral Harry Harris, who is in South Korea to inspect the Ulchi Freedom Guardian (UFG) exercises.

The decades-old defence alliance between Seoul and Washington "represents a very strong military back-up to our diplomats who should take the front line", Harris told reporters at a US air base at Osan south of Seoul.

The allies say the largely computer-simulated UFG drills are purely defensive in nature, but Pyongyang views them as a highly provocative rehearsal for invasion and every year threatens strong military counteraction.

In a statement carried by the official Korean Central News Agency Tuesday, a North Korean army spokesman described Harris and his colleagues as "brass hats of the US imperialist aggressor forces, who would be directly in charge of preemptive strike at the DPRK (North Korea) and war of aggression".

Any attempt to do so would have "catastrophic consequences", it added. 

Solving the current tensions was ultimately up to North Korean leader Kim Jong-Un, said US Forces Korea commander Vincent Brooks, warning that an all-out military confrontation on the peninsula would be "beyond very dangerous and deadly" for both Koreas.

Source AFP