US Secretary of State Antony Blinken has said he shares South Korea's concerns about growing military cooperation between North Korea and Russia, including arms flows and technical support.

Blinken noted at a press conference in Seoul that in exchange for military assistance, the DPRK could receive support from Russia for ballistic missile programmes, as well as nuclear and space technologies.

"We have real concerns about any support for North Korea's ballistic missile programs, for its nuclear technology, for its space launch capacity. We're working to ... identify, to expose and as necessary to counter these efforts," he said.

The United States and its allies have condemned the shipment of weapons and military equipment from North Korea to Russia for use in Ukraine.

North Korea and Russia have denied any arms deals, although their leaders have promised to strengthen military cooperation.

Blinken and South Korean Foreign Minister Park Jin also discussed the so-called extended deterrence strategy to counter threats from North Korea.

In October, the White House announced that the regime of North Korean dictator Kim Jong Un had provided 1,000 containers of military equipment and ammunition to Russia.

South Korea's military intelligence stated that the DPRK provided Russia with more than a million artillery shells for use in the war against Ukraine, and sent advisers to Russia on the use of ammunition.

In addition, Moscow could have received an "unspecified number" of short-range ballistic missiles, anti-tank missiles and MANPADS, as well as rifles, rocket launchers, mortars and shells.