President Lee Jae Myung said South Korea will keep investing steadily in advanced defence technologies. (EPA Images pic)

SEOUL: South Korean President Lee Jae Myung oversaw the country's first test-firing of a domestically developed hypersonic missile, the presidential office said in a statement on Thursday.

Seoul's test of a hypersonic glide vehicle, a manoeuvrable weapon that can change course during flight, came days after North Korea said its leader Kim Jong Un had also overseen his own test of an intermediate-range, hypersonic missile.

"Today, the first test launch of a hypersonic missile we are developing with our own technology was a success. I am truly proud," Lee wrote in a Facebook post.