The United States and China will work to keep their latest tit-for-tat trade spats from escalating into an all-out war, a top US official said Tuesday, just days before a visit by President Barack Obama. Robert Hormats, the US Under Secretary of State for Economic, Energy and Agricultural Affairs, said "tensions, misunderstandings and frictions" were inevitable between major trade partners and could be resolved through talks. "We have trade disputes with a lot of countries with whom we have very close economic ties and they have trade disputes with us," Hormats said in a speech to university students in Beijing ahead of Obama's visit, which begins Sunday.