Expansion in the U.S. manufacturing sector weakened in April as growth in output and new orders fell, according to an industry report released on Friday.

Financial data firm Markit said its final U.S. Manufacturing Purchasing Managers' Index fell to 54.1 in April from 55.7 in March. The preliminary reading was 54.2.

A reading above 50 indicates growth in the sector.

April's growth was the slowest of 2015, and "the survey results raise worries that the dollar's appreciation is hurting the economy," said Chris Williamson, Markit's chief economist.

The index's output component fell to 55.3 from 58.8 in March. The preliminary read was 55.4.

The final reading of the index measuring new orders also weakened in April, coming in at 55.3, under the preliminary reading of 55.4 as well as March's reading of 57.2.

Employment growth also weakened in April from March, Markit said, though the drop was more modest.