Global markets and U.S. stock futures are falling after several explosions rocked Brussels, the capital of Belgium.
Twin blasts hit Brussels airport early Tuesday. They were followed by an explosion in a subway station in the city. Local media said at least 13 people were killed, and 35 wounded.
Brussels is the de-facto capital of the European Union. Many European institutions and international companies are based there. The airport is closed, and train and subway services have been suspended.
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