WASHINGTON — U.S. home prices jumped by a record amount in June as homebuyers competed for a limited supply of available houses, the latest evidence that the housing market remains red-hot.

The S&P CoreLogic Case-Shiller 20-city home price index jumped 19.1% in June compared with a year earlier, the largest increase on records dating back to 2000. The annual price gains in June were higher in all 20 cities than they were in May. Prices are now at record highs in 19 of the 20 cities, with the exception of Chicago.

“The last several months have been extraordinary not only in the level of price gains, but in the consistency of gains across the country,” said Craig Lazzara, managing director of index investment strategy at S&P DJI.

There are signs that the high prices are cooling sales a bit. Sales of existing homes rose 1.5% in July from a year earlier. The number of homes for sale, while still historically low, rose 7% in July from the previous month.

Prices rose by the most in Phoenix, where they soared 29.3% compared with a year earlier, followed by San Diego, with a 27.1% increase, and Seattle, at 25%.