WASHINGTON — Americans increased their spending more slowly in March, raising questions that consumers could be worried about the economy.

The Commerce Department says consumer spending increased just 0.3 percent in March after a 0.9 percent gain in February. Income grew 0.4 percent following a 0.3 percent gain in February.

Consumer spending is closely watched because it accounts for 70 percent of economic growth. It rose at the fastest pace in more than a year in the January-March quarter. But consumers could be cutting back because of weak income gains and a slowdown in hiring.

The amount of income left after paying taxes was up just 0.2 percent in March, after adjusting for inflation. The tiny increase followed two months of declines.