MOSCOW (Yonhap News) -- North Korea and Russia appear to have canceled their plan to hold talks between their leaders later this week, multiple sources here said Tuesday following a series of media reports of the possibility of a trip to Russia by the North's leader, Kim Jong-il.

"It's my understanding that a summit between Chairman Kim Jong-il and President Dmitry Mevedev was known to be scheduled to take place in Russia's Far Eastern region of Vladivostok on June 30 or July 1," a senior Korean government source said. "We have no idea yet why the talks were canceled."

A Russian government source also said the summit plan was scrapped.

An intelligence source privy to North Korea affairs said the two sides might have ditched the summit plan as they failed to narrow differences over the agenda.

Japanese and Russian media reported earlier that the North's leader would likely visit Vladivostok aboard his special train later this week for talks with Medvedev. Neither the North Korean nor Russian governments announced such a summit schedule.

In a presses briefing, meanwhile, U.S. State Department spokeswoman Victoria Nuland said she has no information on the matter. (Yonhap News)