The US has imposed stiff tariffs on both China and the European Union. A professor from King's College London calls it an attack on the global free-trade system. Amid the tensions, he sees opportunity for China and Europe to cooperate.

PROFESSOR KERRY BROWN CHINESE STUDIES, KING'S COLLEGE LONDON "So I suppose we have the opportunity now to really say to China that it is fundamental belief about global system that we need to support because America was once a big supporter but now more and more under Trump attacking the system. It is a very strange situation. So I suppose we have an opportunity to rethink the commitment to global free trade system. China's alliance with us, with Europeans on that, is really a kind of fresh opportunity."