NY -- Standard&Poor's CreditWire 1/8/98 -- Standard&Poor's today lowered its long-term foreign currency ratings on PTT Exploration&Production Public Co. Ltd. (PTT E&P), PTTEP International Ltd., and Advanced Info Service Public Co. Ltd. These downgrades follow the same action taken today on the foreign currency ratings of the Kingdom of Thailand (see related press release). PTT E&P's rating reflects its key public policy role, its close operational ties to the government of Thailand, and its competitive position in the oil and gas industry. A negative rating outlook reflects the outlook on the Kingdom of Thailand. Ratings on Advanced Info Service continue to reflect its solid business base in Thailand for mobile telephones, and the company's