North Korea on Tuesday demanded the return of a cargo ship seized by Washington last week for violating international sanctions, calling it an "illegal act of robbery".

Seventy countries urged North Korea on Friday to scrap its nuclear weapons, ballistic missiles and related programs, decrying the "undiminished threat" posed to world peace.

North Korea launched unidentified projectiles into the sea Saturday, the South Korean military said, in what could be Pyongyang's first short-range missile launch for more than a year as it seeks to up pressure on Washington with nuclear talks deadlocked.

North Korea's close relationship with the Soviet Union cooled in the 1990s under a new Russian power, but were revived in the 2000s as Moscow sought support amid a new standoff with the West. 

Russian President Vladimir Putin and North Korean leader Kim Jong Un vowed to seek closer ties as they met face-to-face Thursday for the first time.

North Korean leader Kim Jong Un arrived in Russia's Pacific port city of Vladivostok on Wednesday for a first summit with Vladimir Putin, as Pyongyang seeks support in its nuclear deadlock with the United States.

South Korea will this week celebrate the first anniversary of a landmark summit between President Moon Jae-in and North Korean leader Kim Jong Un -- but Pyongyang may not take part, Seoul said Monday.

China said Friday leaders from 37 nations and North Korean representatives will attend a summit for its Belt and Road Initiative next week as it hit back at criticism of the massive trade infrastructure project.

Chinese President Xi Jinping's pet project is a $1 trillion programme that includes maritime, rail and road projects in Asia, Africa and Europe.

North Korea on Thursday demanded the removal of US Secretary of State Mike Pompeo from stalled nuclear talks between Pyongyang and Washington, accusing him of derailing discussions.

Activity has been detected at North Korea's main nuclear site, suggesting Pyongyang may be reprocessing radioactive material into bomb fuel since the collapse of a summit with Washington, a US monitor said Wednesday.