The U.S. economy is on strong footing and not facing a financial bubble, Federal Reserve Chairwoman Janet Yellen said Thursday evening.

"This is an economy on a solid course, not a bubble economy," Yellen said at an event in New York City, citing the resilient job growth of recent years.

The central bank carefully monitors markets for signs of instability, she said, but "we certainly don't see those imbalances."

She acknowledged that with short-term interest rates near zero, investors can feel pressure to speculate. Nevertheless, she said, "I certainly wouldn't describe this as a bubble economy."

The topic came up when Yellen was asked to weigh in on gloomy comments about the economy from political candidates. Although he was not mentioned by name, Republican front-runner Donald Trump in particular has regularly argued that the U.S. economy is in a bubble and risks a collapse.

During the question-and-answer session, Yellen also addressed the topic of too-big-to-fail banks.

Moderator Fareed Zakaria posed her a question about Federal Reserve Bank of Minneapolis president Neel Kashkari's campaign to examine the benefits of breaking up big banks. "I certainly share President Kashkari's concern with too-big-to-fail," Yellen responded, but "I feel more positive on the progress we've made" since the financial crisis.

"I'm pleased with where things are going," Yellen said of the Fed's work on supervising Wall Street.