TAMPA - Federal homebuyer tax credits continued to prop up prices in the second quarter. But now that those credits have expired, economists worry that price declines will follow.

The 20 cities tracked by the Standard & Poor's/Case-Shiller home price index showed rising prices in June. It was the third straight month of increases as buyers continued to close deals that were eligible for the credits, according to a quarterly report released Tuesday by S&P/Case-Shiller.

Buyers claiming the credit must close by the end of September, and the majority of them already have.

Home prices nationally were up 4.4 percent in the April-to-June quarter. That came after a decline of 2.8 percent in the January-to-March quarter. The jump largely was because buyers could take advantage of government tax credits of up to $8,000.

In the Tampa-St. Petersburg-Clearwater metro area, prices rose 0.2 percent in the second quarter compared with the first quarter. Second-quarter prices fell 1.6 percent compared with the same quarter a year ago.

Home sales have dropped sharply since incentives expired. Lending standards remain tight, unemployment is stuck near double digits and foreclosures are expected to remain at extraordinary levels.

"We do not take this report as a signal of future strength," wrote BNP Paribas economist Yelena Shulyatyeva.

Prices are expected to fall in the second half of the year. Sales of previously occupied homes plunged in July to the lowest level in 15 years, despite the lowest mortgage rates in decades and bargain prices in many areas.

Tampa-St. Petersburg-Clearwater saw July sales plummet a whopping 19 percent from the same month last year, according to the Florida Realtors group.

Information from The Associated Press was used in this report. Reporter Shannon Behnken can be reached at (813) 259-7804.