National house prices were up 0.9% in April from March, narrowed from the previous monthly gain of 1.1%, according to the latest data from Integrated Asset Services (IAS). The IAS house price index remains 2.8% below levels seen in the same time last year -- widened from the 1.9% yearly depreciation in March. Additionally, the index is down 23.9% from its July 2007 peak. Three of the four US census regions showed gains for the month, including 1.9% in the Midwest, 1.8% in the South and 1.1% in the West. Prices in the Northeast region slipped 0.7% from last month -- marking the region's eighth consecutive monthly loss. IAS found that all four regions declined from the previous-year period, with the South down 4.2%, the Midwest down 2.9%, the West down 2.4% and the Northeast down 1.5%: "Arguably, the housing market is in better shape today than it was a year ago, but it's reasonable to think federal tax credits have propped up home sales and prices to some degree," said IAS president and CEO Dave McCarthy, in a statement. "I'm concerned the end of government support could lead to renewed weakening in the market." April 30 marked the deadline for entering a home purchase contract eligible for the first-time homebuyer tax credit. Qualifying first-time buyers who close by June 30 could receive up to $8,000. But economists warn the jump in pending home sales seen in April and even March ahead of the deadlines may not necessarily translate into sales. Outlook and commentary services firm Econoday, for example, recently noted many of those pending sales may never close, leaving inventory on the market to depress prices further. "[W]e can’t discount the fact that [the IAS index is] positive after so many down months," McCarthy said. "But given all that's in front of us, we can't forget this improvement may be fleeting as well." Write to Diana Golobay.