WASHINGTON (Dow Jones)--President Barack Obama on Friday signed a measure to extend the $8,000 tax credit for first-time home buyers through April and to expand it to certain "move up" homeowners who want to purchase a new home.

Under the measure, existing homeowners who are eligible can claim a $6,500 tax credit on the purchase of a new principal residence as long as they've lived in their current home for at least five years.

Meanwhile, first-time home buyers will have at least five more months to take advantage of the $8,000 credit, which had been set to expire Dec. 1. Both credits will phase out on April 30 of next year, though buyers with contracts by that date would still qualify as long as they close within 60 days.

The extension comes after a lobbying blitz from the home builder, realtor and mortgage-banking industries, which claim the credit has played a crucial role in the housing and broader economic recovery. It was extended Friday as part of legislation to extend jobless benefits.

Obama, in televised remarks after signing the legislation, endorsed the view that the credit was helping the economy rebound. "We want to give even more families the chance to own their own home," he added.

The credit was initially passed last summer but was revamped to be made more generous to home buyers as part of economic stimulus legislation enacted in February.

The measure, which received bipartisan support in Congress, raises the income caps for people eligible for the credit. Individuals with incomes of $125,000 and married couples with incomes of $225,000 may now claim the full credit, up from $75,000 and $150,000, respectively. To qualify, a home's cost may not exceed $800,000.

Federal investigators have discovered rampant abuse of the tax credit, including a four-year old filing to claim the credit. The measure enacted Friday attempts to curb fraud by giving the Internal Revenue Service more oversight authority over the program. Also, the credit is now restricted to those at least 18 years-old who attach a HUD-1 settlement to their tax return.