SEOUL, South Korea — South Korea flight-tested on Thursday its first domestically developed hypersonic weapon, designed to fly at least five times the speed of sound and evade missile defense systems, bringing Seoul closer to what it says could be game-changing weapons capabilities.

There was no immediate response from North Korea, which last week tested its own hypersonic missile that landed in the waters near Japan.

South Korean President Lee Jae Myung attended the test, saying it’s a major step in strengthening the country’s conventional defense capabilities, according to a statement. It did not elaborate where the test took place.

The statement said the weapon separated from its booster rocket at the planned altitude, then descended and maneuvered both vertically and horizontally before hitting a test target. It said once developed, the weapon would be able to strike key targets by surprise in the “Korean Peninsula theater of operations.”

Lee stressed that South Korea “must secure our security through our own strength,” and also inspected the country’s most powerful Hyunmoo-5 ballistic missile on Thursday, his office said. It did not mention any direct comments by Lee on the North.

Tensions between the Koreas have increased in recent weeks after three South Korean soldiers were injured in land mine explosions last month near the heavily armed inter-Korean border.

The South’s military and the U.S.-led United Nations Command concluded the blasts were caused by devices planted by North Korea, which has denied responsibility and ridiculed the South’s demands for an apology.

North Korea has also stepped up weapons testing activity as its leader Kim Jong Un expands his military nuclear program while taking an increasingly hard line toward Seoul.

Kim has so far rebuffed U.S. President Donald Trump’s calls to revive their diplomacy that broke down in 2019, with his government demanding that Washington abandon its “hostile” policy toward Pyongyang and drop demands for its denuclearization as a precondition for talks.