The manufacturing Purchasing Managers' Index, or PMI, fell to 48.5 in May from 52.4 in April.

A PMI reading below 50 suggests contraction in the sector.

"May's survey highlighted the continuation of the themes seen in recent surveys, namely around high inflation – especially for fuel/energy costs – and the market instabilities caused by the war in Ukraine," Paul Smith, economics director at S&P Global Market Intelligence, said.

Production and new orders declined in May and was the sharpest for the two years. New export orders fell for the third month in a row. Input prices and output costs increased in May. Lead times deteriorated and backlogs of works increased.

Employment rose for the sixth month in a row in May and inventories for purchases increased for the fourteenth straight month. Confidence for the coming year's production level softened due to the worries over inflation. The overall sentiment weakened to the lowest in nineteen months.