Seoul, Dec 19 (IANS): North Korea has conducted an "important final-stage" test at its rocket launching facility on putting a military reconnaissance satellite into orbit, with a plan to complete preparations for the project by April next year, Pyongyang's state media said on Monday.

The test was conducted at the Sohae Satellite Launching Ground on Sunday mainly to "evaluate the capabilities of satellite photography and data transmission system and ground control system", North's official Korean Central News Agency (KCNA) said in a reported.

The country fired a vehicle carrying a "test-piece satellite" at a lofted angle to an altitude of 500 km, Yonhap News Agency quoted the KCNA report citing a National Aerospace Development Administration spokesperson as saying.

North Korea will "finish the preparations for the first military reconnaissance satellite by April 2023", the spokesperson said, adding that the latest test was the "final gateway process" for the launch of such a satellite.

South Korea's Joint Chiefs of Staff said on Sunday it detected the launches of two medium-range ballistic missiles (MRBM) from Tongchang-ri areas into the East Sea.

The missiles, fired at steep angles, flew some 500 km, it added.

The North's media did not mention whether leader Kim Jong-un inspected Sunday's firing in person.

The Sohae rocket launching facility in Tongchang-ri, not far away from the border with China, is a site where North Korea tested a high-thrust solid-fuel rocket engine last week for a "new-type strategic weapon system".

North Korea launched Hwasong-17 intercontinental ballistic missiles in February and March, claiming they were test-launches of spy satellites.