SEOUL (Reuters) - South Korea plans to buy two Israeli early warning radar systems, it said on Tuesday, as it reinforces air defenses against North Korea despite fast-improving relations.

The decision to adopt the two Green Pine Block C radar systems, built by ELTA Systems, a subsidiary of state-owned Israel Aerospace Industries, was made at a defense acquisition committee, Seoul’s arms procurement agency, DAPA, said.

DAPA did not specify the value of the order, but an official at the defense ministry put it at 330 billion won ($292 million), saying the systems would be deployed in the early 2020s.

The project is intended to boost South Korea’s capabilities to “detect and track ballistic missiles from a long distance at an early stage”, DAPA said in a statement. It did not mention North Korea.

But South Korea’s defense ministry said last December it would buy additional early warning radars after North Korea successfully tested an intercontinental ballistic missile and declared completion of the “state nuclear force” a month earlier.

Reclusive North Korea and the rich, democratic South are technically still at war because their 1950-53 conflict ended in a truce, not a peace treaty.

North Korea has for years pursued nuclear and missile programs in defiance of U.N. sanctions. But the two Koreas moved to defrost their relations this year, clinching a comprehensive military agreement at their summit in September in Pyongyang aimed at defusing military tensions around the heavily fortified border.

North Korean leader Kim Jong Un and U.S. President Donald Trump pledged to work toward denuclearization at their landmark June summit in Singapore, but the agreement was short on specifics and negotiations have made little headway since.