MOSCOW (Reuters) - North Korean leader Kim Jong-il repeated his readiness to return to stalled nuclear talks "without any preconditions" in an interview with the Russian state news agency Itar-Tass published on Wednesday.

The comments came amid a flurry of intensified diplomacy by Russia, China and the United States on trying to end North Korea's nuclear program after talks collapsed in late 2008.

The United States and North Korea plan to meet on Monday and Tuesday in Geneva, a source familiar with the matter said, for discussions likely to focus on whether nuclear talks might resume.

"Our principal position that the six-party talks should be swiftly resumed without any preconditions remains unchanged," Kim said in a written response to questions from Itar-Tass.

Russia and China have pressed their reclusive and impoverished neighbor to return to the six-nation talks though the United States, Japan and South Korea say Pyongyang must first show it is serious about getting rid of its nuclear capabilities.

During a rare visit to Russia last month, Kim promised to consider suspending nuclear arms tests and production if international talks on Pyongyang's atomic program resume.

Since the August meeting with President Medvedev, Kim's first public visit to Russia since 2002, relations with the Kremlin have improved.

Russia resumed traffic along a repaired rail line to North Korea and has aired plans to build a gas pipeline and even hold joint naval exercises.

"On these projects, North Korea and Russia are now rapidly implementing practical measures for cooperation in the field of energy, including on the laying of a pipeline," Kim told Tass.

"I am certain that the friendship and cooperation between our two countries will develop and strengthen in all spheres including politics, economy, culture and military affairs."

(Writing by Alissa de Carbonnel)