WASHINGTON—The recession is easing? Not so fast. An unexpected drop in sales of just about everything from cars to clothes sent a sobering message Tuesday: The economy is still vulnerable.

That cautionary guidance was seconded by President Barack Obama and Federal Reserve Chairman Ben Bernanke, though they had encouraging words as well. Bernanke spoke of “tentative signs” that at least the economy is declining more slowly, and Obama repeated his recent analysis that he sees “glimmers of hope.”

With Americans still losing jobs by the thousands, a major fear is that people will cut back even further on their spending, and that could plunge the economy into a sharper tailspin.

Tuesday’s report that retail sales fell 1.1 percent in March deepened concern.

Improvements in a string of other economic reports over the past few weeks—including home and auto sales, home building and other consumer-spending barometers—had raised optimism that the economy’s descent might be slowing.

Obama and Bernanke cited those improvements in separate speeches Tuesday. But they also made clear the economy is not out of danger and that potential pitfalls lie ahead.