The critical question is whether US and China can strike a deal by the March 1 deadline because if they succeed, a cloud will be lifted off the world economy.
Chinese factories making everything from bikes to tyres, plastics and textiles are moving assembly lines abroad to skirt higher customs taxes on their exports to the United States and elsewhere.
She added that the good functioning of the world economy depends on countries working together as partners.
Canada's retaliatory tariffs took effect Sunday against American products including Florida orange juice, ketchup and Kentucky bourbon.
China's foreign minister called on the international community to oppose the United States' recent trade moves, saying they threatened global economic growth.