International concerns about a possible North Korean nuclear test

Kim Jong-il may have crossed the border into China to explain his military provocations to uneasy allies in Beijing. According to the South Korean media, satellites have tracked a special North Korean train, the usual form of transport for Mr. Kim, entering Chinese territory. If confirmed, it would be his second trip to Beijing in less than a year - an unheard-of flurry of diplomacy for a notoriously travel-shy figurehead. The reports are impossible to verify, but they come amid growing signs of Chinese anger with Mr. Kim over last month's missile tests, and regional anxiety about his next move. Earlier this month, the South Korean president, Roh Moo-hyun, requested an emergency summit with Beijing's leaders.