Added to the pressure on ties is the question of Tibet, where the 50th anniversary of a failed uprising against Chinese rule was marked Tuesday with a harsh security clampdown to prevent any protests.

• 西藏问题也给关系增加了压力，在那里，星期二是西藏反对中国统治起义失败50周年，特点是会有严格的安保压制，防止任何抗议活动。