Japan on Wednesday protested to Russia over the arrest of a Japanese journalist on suspicion of spying, demanding Moscow's explanation, access to the man in custody and humane treatment for him. The arrest on Tuesday is a latest flap between the two countries whose tensions have spiked after Russian President Vladimir Putin’s August visit to one of four disputed Kuril Islands. In Tokyo, a senior Foreign Ministry official Kimitake Nakamura summoned Russian Ambassador to Japan Nikolay Nozdrev and lodged the protest. The island dispute has prevented the two countries from signing a peace treaty formally ending their wartime hostilities