Russia and North Korea solidify partnership, vowing mutual assistance against 'aggression'

The U.S. said it was likely Putin would seek military aid while in Pyongyang.

Putin wrapped up his meeting in North Korea after about 11 hours of communication with Kim, according to Russian media. Putin was personally escorted back to his plane at Pyongyang airport by Kim.

The two heads of state met in Pyongyang on Wednesday as part of Putin's official state visit, his first trip to the secretive country in 24 years. The negotiations are the latest in a series of discussions about trade and economic relations between the two countries, both of which are subject to Western sanctions.

Putin and Kim held face-to-face talks in eastern Russia in September, which were followed by rounds of lower-level talks in both Pyongyang and Moscow.

"As a result of your visit to Russia last year, we made much headway in developing contemporary interstate relations," Putin said in his opening statement, according to Interfax, a Russian news agency. "A new fundamental document has been drafted to lay a long-term foundation for our relations."

North Korean state media on Wednesday said Kim's government was hoping the meetings would lead to "deepening economic and trade relations" with Russia.

The U.S. State Department has said North Korea has shipped arms -- including dozens of ballistic missiles and more than 11,000 containers of munitions -- to Russia for use in its war against Ukraine. U.S. officials said it was likely that Putin would ask for further military aid while in Pyongyang.

"We have seen him get incredibly desperate over the past few months and look to Iran to rebolster the military that he's -- military equipment that he has lost in Ukraine, to look to North Korea to rearm himself," Matthew Miller, a state department spokesperson, said during a briefing on Tuesday. "And so I'm quite certain that that is what he's up to."

Putin promised their new agreement, which was signed prior to Wednesday's negotiations, would be the cornerstone of a long-term relationship between the two countries, according to Interfax, the Russian news agency.

Both leaders sought to position their two-hour meeting as an affront to the United States and its Western allies. As Putin thanked Kim for North Korea's support for his invasion of Ukraine, he said the war was a "fight against the imperialist hegemonistic policies of the U.S. and its satellites against the Russian Federation," Interfax reported.

North Korea on Wednesday hosted a welcome ceremony for Putin, who had arrived late Tuesday and stayed at a state guest house overnight.

Kim had greeted Putin as he stepped off his plane at Pyongyang International Airport. The two traveled in Putin's private vehicle, passing "through charmingly lit streets" to the guest house where Putin stayed, North Korean state media reported. The two "exchanged the inmost thoughts" as they drove, the report said.

The pair on Wednesday morning strolled through Kim Il Sung Square along a red carpet. They were greeted by throngs of North Koreans waving flowers, balloons and flags.

ABC News' Natalia Shumskaia and Joe Simonetti contributed to this report.