New York: Oil prices reversed early gains to end sharply lower on Thursday, as official data showed US crude inventories dropped by less than expected. The West Texas Intermediate for August delivery tumbled $2.29 to settle at $45.14 a barrel on the New York Mercantile Exchange, while Brent crude for September delivery dropped $2.40 to close at $46.40 a barrel on the London ICE Futures Exchange, Xinhua news agency reported. US crude supplies of last week lost 2.2 million barrels to 524.4 million barrels, below market consensus of a 2.5-million decline, according to the Energy Information Administration (EIA)' s weekly report released on Thursday. The industry-funded American Petroleum Institute reported Wednesday that crude supplies fell by 6.7 million barrels last week. Meanwhile, worries about global economic uncertainty after Britain's exit from the European Union continued to weigh on the market.