SEOUL • US President Donald Trump and his South Korean counterpart Moon Jae In have agreed to revise a joint treaty to allow the South to build more powerful and longer-range ballistic missiles in a response to North Korea's missile and nuclear tests.
Mr Trump has also given "conceptual" approval to the purchase by the South of billions of dollars of US military hardware.
Both leaders spoke on the phone on Friday about North Korea's "continued destabilising and escalatory behaviour" and agreed to strengthen their alliance through defence cooperation and South Korea's defence capabilities, the White House said in a statement.
"President Trump provided his conceptual approval of planned purchases by South Korea of billions of dollars in American military equipment," the White House said.
The spokesman for Seoul's presidential office Park Soo Hyun said the two leaders reached an agreement in principle to loosen - "to the extent hoped by the South Korean side" - limits on Seoul's ballistic missile capability.
Under a bilateral agreement with the United States, South Korea is currently restricted to ballistic missiles with a maximum range of 800km and a payload of 500km. The South wants the maximum warhead weight doubled to one tonne, and the Pentagon has said it was "actively" considering the revision.
Signed with the US in 2001 - the year South Korea joined the Missile Technology Control Regime - the agreement initially limited Seoul to rockets with a range of just 300km due to US concerns about triggering a regional arms race in North-east Asia.
However, after a long-range rocket test by North Korea in 2012, Seoul managed to negotiate the near three-fold increase in the range limit to 800km, putting North Korean military facilities which were previously out of range within reach, as well as parts of China and Japan.
Impoverished North Korea and the rich, democratic South are technically still at war because their 1950-1953 conflict ended in a truce, not a peace treaty. The North regularly threatens to destroy the South and its main ally, the US.
North Korea sharply raised regional tensions last week with the launch of its Hwasong-12 intermediate-range ballistic missile that flew over Japan and landed in the Pacific. That followed the test launch of two long-range ballistic missiles in July in a sharply lofted trajectory that demonstrated a potential range of 10,000km or more, which would put many parts of the US mainland within striking distance.
The US and South Korean leaders on Friday pledged to continue to apply strong diplomatic and economic pressure on North Korea and to make all necessary preparations to defend against the growing threat from the North, the White House said.
Calls are also mounting in South Korea for Seoul to build nuclear weapons of its own to defend itself as nuclear-armed North Korea's missile stand-off with the US escalates.
The South, which hosts 28,500 US troops to defend it, is banned from building its own nuclear weapons under a 1974 atomic energy deal it signed with the US which instead offered South Korea a "nuclear umbrella" against potential attacks.
REUTERS, AGENCE FRANCE PRESSE