Key Asian markets ended mixed on Tuesday, ahead of a key German ruling on the euro zone's bailout funds. Japan's Nikkei-225 index fell 0.7 percent; China's Shanghai Composite index also dropped 0.7 percent; and South Korea's Kospi index shed 0.2 percent.

But Hong Kong's Hang Seng index rose 0.2 percent; and and Singapore's Straits Times index added 0.3 percent. China, meanwhile, posted a wider-than-expected trade surplus in August, as imports unexpectedly contracted. Exports rose 2.7% in August from a year earlier, indicating relatively weak overseas demand. Imports dropped a surprising 2.6%, against expectations for a small rise.

The European markets fell, amid concern that developments in Spain or Germany could derail the European Central Bank's bond-buying plan. So key stock indices, UK's FTSE-100 and France's CAC-40 lost 0.4 percent, each, while Germany's DAX fell 0.2 percent in intra-day trade on Tuesday.