Nigeria, June 11 -- Rising food prices may soon top energy costs as the chief driver of inflation across emerging markets, with African economies likely to be worst hit, according to a new report by S&P Global Ratings.

"Food prices are likely to start heading higher in the coming months," the ratings agency said in the report published on Wednesday, noting that fertiliser prices have surged sharply on account of supply constraints. It added that there is typically a lag between increases in fertiliser costs and their eventual impact on food prices.

The warning comes amid growing concerns over disruptions to global energy and commodity supply chains, following escalating tensions in the Middle East, particularly around the Strait of Horm...