Six Poseidon maritime patrol aircraft worth $2.1 billion form the bulk of the sale, the Defense Security Cooperation Agency said in a statement.

A second contract covers 64 Patriot missiles and support worth $501 million, the agency said.

Congress has 15 days to oppose the sale but that would be unlikely given the close relationship between Seoul and Washington, which stations tens of thousands of its troops on South Korean soil to defend against the threat from nuclear-armed North Korea.

The P-8A Poseidon, made by Boeing, can be used for intelligence and reconnaissance as well as for anti-submarine and anti-surface warfare.

"The proposed sale will support US foreign policy and national security objectives by enhancing Korea's naval capabilities to provide national defense and significantly contribute to coalition operations," the agency said.

The Patriots, to be made by Texas-based Lockheed-Martin, are designed to intercept tactical ballistic missiles, cruise missiles and other airborne threats.

South Korea will use the system "to improve its missile defense capability, defend its territorial integrity and deter threats to regional stability," the statement said.

"The proposed sale of this equipment and support does not alter the basic military balance in the region."

US President Donald Trump and North Korea's leader Kim Jong Un pledged at a historic June summit to denuclearize the Korean peninsula.

However, no details were agreed, and Washington and Pyongyang have sparred since over what that means and how it will be achieved.

sl/it/ft

LOCKHEED MARTIN

BOEING