Japan has demanded that Russia let its diplomats visit a detained Japanese journalist and release him, The Japan Times and AFP reported. Russia accuses the reporter, Yuki Imai of the Hokkaido Shimbun newspaper, of spying, a charge Japan denies.

Kimitake Nakamura, a senior official at Japan's Foreign Ministry, met a Russian Foreign Ministry official in Moscow on Tuesday to discuss the case, The Japan Times reported. "Japan conveyed its position that it calls for consular access to the Japanese national detained in Russia to be granted as soon as possible, as well as the individual's immediate release," Chief Cabinet Secretary Minoru Kihara said Wednesday.

On Tuesday, Kihara said it was "extremely regrettable" that Japanese diplomats had not been able to visit the journalist, AFP reported. A protocol signed between Japan and the Soviet Union, which still applies to Russia, guarantees consular access within four days of an arrest, he said.

Imai was arrested on Sakhalin island in Russia's Far East about a week ago, AFP reported. The BBC reported that he was detained a day before he was due to leave Russia and was flown to Moscow, where a court ordered him held until December 12.

Russia's foreign ministry has said Imai is accused of "conducting espionage activities on Russian territory," according to AFP. Russia's FSB security service said the person worked for Japanese intelligence. "Tokyo's attempts to use its correspondents in Russia, who hold foreign journalist status, to gather information aimed at undermining our country's security are regrettable," ministry spokeswoman Maria Zakharova said, the BBC reported. People convicted of spying in Russia can face up to 20 years in prison.

Japanese Prime Minister Sanae Takaichi rejected the claim, saying "there is no such fact," AFP reported. Japan also summoned Russia's ambassador to protest.

The arrest comes amid a long dispute over islands that Russia calls the Kurils and Japan calls the Northern Territories. Russian President Vladimir Putin visited the islands in August.

What we know: Imai is being held in Moscow on spying charges, and Japan says Russia has not allowed a consular visit.
What we don't: When Japanese diplomats will be allowed to see him, and when his trial will begin.