The head of the upper house of the Russian parliament says North Korea is not ready to return to the six-way nuclear talks.

Federation Council Speaker Sergey Mironov made the statement during an interview with the “Ria Novosti” Russian news agency on Thursday. He had visited the North for two days last week.

Mironov said the North Korean leaders he met with spoke in a resolute tone on Pyongyang’s nuclear issue. He said the North’s unprecedented tone with Russia apparently comes after Moscow joined other U.N. members in adopting a resolution sanctioning the North for conducting a second nuclear test in May.

Meanwhile, Russian media are reporting that Mironov delivered a letter from Russian President Dmitry Medvedev to North Korean leader Kim Jong-il. However, the North has yet to confirm this claim.