OIL prices continued to rise in early trading on Thursday following renewed concerns about tightness of supplies. In London, the price of benchmark Brent crude for July delivery edged up nine cents to $28,70 a barrel. Dealers attribute the increase mainly to the latest US data on supplies, although they add that speculative buying is also thought to have lifted the price. On Tuesday, the American Petroleum Institute revealed that crude oil stocks have fallen by 1326-million barrels to 3035- million in the week to May 19 from the previous week.