At a time when Kim Jong Un is visiting Russia for his meeting with President Vladimir Putin, North Korea fired an unspecified ballistic missile toward the East Sea on Wednesday.

The Joint Chiefs of Staff announced the launch but gave no further details, pending an analysis, reports Yonhap news agency in South Korea.

North Korea had last fired two short-range ballistic missiles on August 30.

Meanwhile, Kim Jong Un is currently in Russia to attend his summit with Putin.

However, the place and the time when the meeting will take place is still not clear.

Analysts have predicted that North Korea may agree to supply Russia with ammunition and weaponry for its war in Ukraine. Moscow, in return, may agree on a weapons-related technology transfer to Pyongyang, such as those involving spy satellites and nuclear-powered submarines, reports Yonhap.

The US warned it would 'aggressively' enforce existing sanctions and add new ones if North Korea supplies arms to Russia for its ongoing war against Ukraine.

"I will remind both countries that any transfer of arms from North Korea to Russia would be in violation of multiple United Nations Security Council resolutions," US State Department spokesperson Matthew Miller told reporters.

"We, of course, have aggressively enforced our sanctions against entities that fund Russia’s war effort, and we will continue to enforce those sanctions and will not hesitate to impose new sanctions if appropriate," he said.

The US official, however, did not specify whether the sanctions will be imposed against one of the nations or both.