Two Japanese tourists were detained in China following a "prank" at the Great Wall that sparked public outrage.

Two Japanese tourists in their 20s were detained for two weeks in China then deported for taking photos showing exposed buttocks at the Great Wall, local media reported. The incident at the World Heritage site near Beijing concerned a man who showed his bottom and a woman who took photos, NTV and other Japanese media outlets reported on Thursday.

China has lashed out at accusations it is endangering maritime safety made by top diplomats from the Group of 7 industrialized democracies.

G7 foreign ministers took a tough stance on China on Friday, stepping up language on Taiwan and omitting some conciliatory references from past statements, including to "one China" policies.