San Francisco Federal Reserve Bank President John Williams said on Monday that he expects the Fed to raise its interest rates "sometime later this year".

"Given the progress we've made and continue to make on our goals, I view the next appropriate step as gradually raising interest rates, most likely starting sometime later this year," he said.

He pointed out that he sees the signs of overheating of the U.S. housing market.

"I am starting to see signs of imbalances emerge in the form of high asset prices, especially in real estate, and that trips the alert system," Williams said.