Oil dips on concerns of delay in U.S.-China trade deal until next year

SINGAPORE (Reuters) - Oil prices retreated on Thursday after gaining more than 2% in the previous session on bullish U.S. crude inventory data, as a fresh spat over Hong Kong fuelled concerns of a further delay in any U.S.-China trade deal.The trade war between the world's two biggest economies has hit global growth prospects and dominated the outlook for future oil demand.Trade experts have warned the first phase of a trade deal could slide into next year, while markets are wary negotiations..