Low inventory levels of moderately priced homes continued to push up home prices in U.S. metropolitan areas, the National Association of Realtors (NAR) said on Thursday.

The national median existing single-family home price in the third quarter was 266,900 U.S. dollar, up 4.8 percent from the third quarter of 2017, according to NAR's quarterly Metropolitan Median Area Prices and Affordability report.

Single-family home prices increased in 166 out of 178 metro statistical areas, with 18 areas seeing double-digit rises.

"Though inventory is more than adequate on the upper-end market, the insufficient supply of low to mid-priced homes in metro markets with strong job growth continues to drive up prices and push prospective buyers out of the market," said Lawrence Yun, NAR's chief economist.

As a result, total existing-home sales, including single family homes and condos, decreased 2.6 percent to a seasonally adjusted annual rate of 5.273 million in the third quarter, down from 5.413 million in the second quarter.

"A strong economy and consistent job growth should be driving up home sales. However, would-be home buyers are struggling to find a home they can afford," said Yun.

At the end of the third quarter, there were 1.88 million existing homes available for sale. The average supply during the third quarter was 4.3 months.

Four of the five most expensive housing markets in the third quarter were in California, the other one was urban Honolulu, Hawaii. The median existing single-family prices in these areas ranged from 650,000 USD to 1,300,000 USD.