MOSCOW, Russia -- Russian authorities have detained an American and a British citizen in the far east after the pair made a rare crossing by foot of a frozen 56-mile stretch of the Bering Strait, officials said Tuesday. The two were arrested in Chukotka province for failing to register with the authorities, Andrei Orlov, spokesman for the Federal Security Service's (FSB) northeastern border guard division, said on NTV television. All visitors are required to register with police within three days of their arrival in Russia, even if they have visas. Russian authorities did not identify the two or say when...