SEOUL, Dec 31 (AFP) - North Korea fired three ballistic missiles toward the sea east of the Korean Peninsula on Saturday, the South Korean military said.

The launches were the latest in an unprecedented number of missile tests conducted by North Korea this year, as Pyongyang presses on with weapons development amid speculation it could test a nuclear weapon for a seventh time.

The three short-range ballistic missiles were fired from around 8 am local time (2300 GMT) from North Hwanghae Province, south of the capital Pyongyang, South Korea's Joint Chiefs of Staff said.

All three flew at an altitude of around 100 kilometres (62 miles) and covered a range of around 350 kilometres (217 miles), Kyodo news agency reported, citing Japan's defence ministry.

The launches came a day after South Korea's defence ministry announced it had successfully conducted a test flight of a solid-propellant space launch vehicle.

On Monday, five North Korean drones crossed into South Korea, prompting the South's military to scramble fighter jets and attack helicopters to try to shoot them down, in the first such intrusion since 2017.

Relations between North Korea and U.S.-ally South Korea have grown more tense since South Korean President Yoon Suk-yeol's conservative government took over in May, promising a tougher stance toward the North.

Not counting Saturday's launches, North Korea has fired around 70 ballistic missiles this year, Yonhap news agency said, including about eight intercontinental ballistic missiles (ICBM).

North Korean state media KCNA had yet to mention the launches, but said on Saturday that leader Kim Jong Un had presided over a party meeting on Friday to decide policy and strategy for 2023.