The dollar index, a prorated measure of the U.S. dollar against six major currencies, rose to 76.31 from Friday's 75.441. The euro dropped to $1.4007 against the dollar, the lowest point in two months.
Signs of slower demand from China were found in a report from HSBC that pegged the country's purchasing managers index at 51.1 in April from 51.8 in March, MarketWatch reported.
On the New York Mercantile Exchange on Monday, June delivery crude oil lost 93 cents to reach $96.77 per barrel. Home heating oil prices shed 1.67 cents to $2.843 per gallon. Reformulated blendstock gasoline prices lost 1.4 cents to $2.8875 per gallon.
Henry Hub natural gas prices lost 2.1 cents to $4.325 per million British thermal units.
At the pump, the national average price of unleaded gasoline dropped to $3.843 per gallon from Sunday's $3.852, AAA said.