Kennedy at the time was greatly concerned over reports that the Chinese Communists were secretly conducting nuclear explosions at Lop Nor in Northwest China—a sure indication they were working on atomic weapons. This was the period when Moscow and Peking were still close to each other, otherwise it might have been possible for the United States to devise a way to neutralize Peking's nuclear potential at an early stage. At their meeting Kennedy asked Chen many questions about Lop Nor. Could he have been thinking of a preventive surgical strike?]