North Korean leader Kim Jong-un, left, inspects a performance test of suicide drones produced by an affiliated institute of the Unmanned Aerial Technology Complex and businesses in this file photo provided by the North's official Korean Central News Agency, Nov. 14. Yonhap

North Korea appears to be preparing to deploy additional troops and military equipment to Russia, possibly including suicide drones, in support of Moscow's war against Ukraine, South Korea's military said Monday.

The assessment came as North Korea is believed to have sent thousands of troops to fight for Russia in its war against Ukraine, with the number of casualties estimated to be around 1,100, according to the South's spy agency.

"A comprehensive assessment of multiple intelligence shows that North Korea is preparing to rotate or increase the deployment of troops (in Russia), while currently supplying 240 millimeter rocket launchers and 170 mm self-propelled artillery," the Joint Chiefs of Staff (JCS) said.

"There are also some signs of (the North) moving to manufacture and supply suicide drones, first unveiled during Kim Jong-un's on-site inspection in November," the JCS said, attributing the move to the North's efforts to gain practical warfare experience and modernize its conventional weapons system.

Last month, the North's state media reported that Kim observed an on-site test of various types of suicide attack drones and called for the full-scale production of the weapons that are increasingly becoming important in modern warfare due to their cost effectiveness.

The military is monitoring the situation following signs that the North has expressed its intent to provide loitering munitions to Russia, a JCS official told reporters, without providing further details.

The JCS said no specific signs of provocation have been detected from the North, adding that the country is focusing on expanding its military cooperation with Russia and stably managing its domestic environment ahead of a key year-end plenary party meeting.

The military, however, did not rule out the possibility of the North staging a surprise military provocation timed around the major political event, such as launching an intermediate-range ballistic missile (IRBM) tipped with a hypersonic warhead.

In April, North Korea said it successfully launched a new IRBM tipped with a hypersonic warhead, a claim that Seoul assessed as "unsuccessful," although it acknowledged that Pyongyang appears to have made some progress in its hypersonic weapons program.

North Korean soldiers test an electric barbed-wire fence using an animal that appears to be a goat at an unidentified location, in this photo provided by South Korea's Joint Chiefs of Staff, Dec. 23. Yonhap

Going forward, the JCS projected the North to continue with "gray zone" provocations next year, such as launching trash-carrying balloons and carrying out GPS jamming attacks.

"As the North has to concentrate on supporting Russia next year, it is likely to feel burdened by (the possibility of) causing military tension or conflicts that could lead to the creation of a new war front," the JCS said.

"But the need for cooperation on information sharing with the U.S. as well as establishing a firm readiness posture are vital as there is also the possibility of the North attempting various provocations, such as an intercontinental ballistic missile launch or a nuclear test to enhance its bargaining power against the U.S."

The JCS also noted that the North's construction activities to reinforce border security are still under way, unveiling photos of North Korean troops testing electric barbed-wire fences with what appeared to be goats.

Since April, the North has mobilized thousands of soldiers to reinforce roads and install anti-tank barriers. (Yonhap)