North Korean leader Kim Jong Un left Russia on Sunday after a visit that focused heavily on military cooperation between the two countries.

At the end of his visit, reports said Kim received explosive drones and protective clothing as gifts.

How Kim's Russia tour ended

Kim departed for home aboard his armored train from Russia's Far Eastern city of Artyom. The Ria Novosti agency published a video and said a "departure ceremony" was held before Kim's train set off on a journey of around 250 kilometers (155 miles) to the border.

Russia's TASS news agency said the North Korean leader had "received five kamikaze drones and a 'Geran-25' reconnaissance drone with vertical takeoff."

In addition, the agency also said the governor of the Primorye region Oleg Kozhemyako "offered Kim Jong Un a set of bulletproof protection" and "special clothing not detectable by thermal cameras."

Earlier on Sunday, Kim toured a university and took in a walrus show at an aquarium. A video released by Russia's RIA Novosti state news agency showed Kim dressed in a black suit and accompanied by his top officials, walking through the campus of the Far Eastern Federal University in Russky Island. 

Kim visited the Primorsky Aquarium, Russia's largest aquarium, to watch performances by beluga whales, bottlenose dolphins, fur seals, and the famed walrus "Misha," according to Russian state media. 

Kim's trip raises concerns

During his visit to Russia, Kim conducted inspections of Russian nuclear-capable strategic bombers, hypersonic missiles, and warships on Saturday. 

North Korean state media said Kim had discussions with Russian Defense Minister Sergei Shoigu to expand "strategic and tactical coordination" between their countries' militaries. The pair were said to have engaged in discussions to enhance military cooperation, marking what Pyongyang describes as a "new era" in bilateral relations.

Kim's visit is a rare occurrence for the North Korean leader, who seldom leaves his country.

Earlier in the week, he met Russian President Vladimir Putin, where discussions covered military matters, the situation in Ukraine, and the deepening of cooperation between the two countries.

The warming military ties between North Korea and Russia have raised concerns among the United States and its allies, particularly in light of Russia's ongoing invasion of Ukraine and North Korea's progress in missile and nuclear development.

Both South Korea and the US expressed on Friday that military cooperation between North Korea and Russia would violate UN sanctions against Pyongyang, and they pledged to ensure consequences for such actions. 

South Korea's President Yoon Suk Yeol said the international community "will unite more tightly" to cope with deepening military cooperation between Russia and North Korea.

Russia has also talked about the possibility of military collaboration with North Korea. Moscow is actively exploring the possibility of joint military exercises with North Korea, as confirmed by Shoigu to Russian media.

Shoigu had previously visited Pyongyang in July, where he toured a weapons exhibition with Kim.

tg/rc (AP, Reuters)