Reuters reported that Kerry suggested to a small group of reporters that some Americans don't understand tighter spending, partially motivated by congressional Republicans, could have a negative effect on U.S. engagement abroad.
"There's a new isolationism," he said, as quoted by Reuters, adding "We are beginning to behave like a poor nation."
Kerry cited limited support from Congress for U.S. airstrikes in Syria last fall as evidence of "new isolationism."
The secretary of state expressed concern that the slight decline in the State Department's budget, which which will be included in the budget President Barack Obama is expected to present Tuesday, would "diminish our ability to do things."
"This is not a budget we want. It's not a budget that does what we need," Kerry said, as quoted by Reuters. "It was the best the president could get. It's not what he wanted."