Consumer confidence crumbled in April as rising gasoline prices undermined how Americans feel about the prospects for economic growth, a widely watched gauge of the economy showed on Tuesday.

The New York-based Conference Board said its Consumer Confidence Index dropped to 104.0, in April, down from a revised 108.2 in March. Analysts had expected a reading of 105. The April reading was the lowest since August, when the index was at 100.2.

The Present Situation Index, which measures how shoppers feel now about economic conditions, decreased to 131.3 from 138.5 in March. The Expectations Index, which measures consumers' outlook for the next six months, declined to 85.8 from 87.9.

"Unlike the decline in March, which was solely the result of apprehension about the short-term outlook, this month's decline was a combination of weakening expectations and a less favorable assessment of present-day conditions," said Lynn Franco, director of The Conference Board Consumer Research Center, in a statement. "Rising prices at the gas pump continue to play a key role in dampening consumers' short-term expectations."

Franco noted that the decline in the Present Situation Index — the first decline in six months — needs to be watched closely in the months ahead.