The US State Department has cleared $US314 million ($A458 million) in possible sales of air defence missiles to South Korea as tensions re-emerge on the Korean peninsula.
South Korea, a key Asian ally of the United States, asked to buy up to 94 SM-2 missiles used by ships against air threats, along with 12 guidance systems and technical assistance, the US Defence Security Cooperation Agency (DSCA) said on its website.
The agency, a unit of the Department of Defence, delivered certification on Thursday notifying the US Congress of the possible sale.
The proposed sale comes after North Korea recently criticised South Korea's defence purchases from the US, including the arrival of the first F-35 stealth aircraft.
With denuclearisation talks stalled after a second summit between North Korea and United States broke down in Hanoi in February, North Korea went ahead with more weapons tests this month.
The reclusive North and the rich, democratic South are technically still at war because their 1950-53 conflict ended in a truce, rather than a peace treaty.
South Korea already uses SM-2 missiles developed by US company Raytheon, but is building more missile defence-capable destroyers equipped with the weapon.
North Korea has boasted about its indigenous surface-to-air missiles.
Separately, Japan, another key US ally in the region, was also cleared to buy $US317 million worth of medium-range air-to-air missiles from Washington, the DSCA said.
