Oil falls on U.S. crude build, Brexit risk

By Devika Krishna Kumar NEW YORK (Reuters) - Oil prices fell about 2 percent in extended trading on Tuesday as data showed a surprise build in U.S. crude inventories last week, adding to the market's nervousness around Britain's vote next week on whether to leave the European Union. Data from the American Petroleum Institute (API) showed U.S. crude inventories rose by 1.2 million barrels in the week to June 10 to 536.7 million, compared with analysts' expectations for a decrease of 2.3 million b