North Korea's leader, Kim Jong-un, has reaffirmed the alliance between Pyongyang and Moscow in a letter sent to Russia's President Vladimir Putin, and stressed his "unconditional support" to the country in full rapprochement between the two and as the invasion of Ukraine progresses. Kim has transferred to Putin his "warmest congratulations" for Russia Day. "The two countries have sincerely strengthened and developed their camaraderie and trust r…