Pending sales of previously owned U.S. homes rose at a faster-than-expected pace in June, a real estate trade group said on Tuesday, more evidence the housing market was starting to claw out of a three-year slump.

The National Association of Realtors said its Pending Home Sales Index, based on contracts signed in June, rose 3.6 percent to 94.6. It was the fifth straight month of advance and the first such streak in six years, the industry group said.

May's index was revised upwards to 91.3 from 90.7, while the percentage increase was bumped up to 0.8 percent from 0.1 percent. Analysts polled by Reuters had forecast pending home sales to rise 0.6 percent in June.

Historically low mortgage interest rates, affordable home prices and large selection are encouraging buyers who've been on the sidelines, said NAR chief economist Lawrence Yun.

The Pending Homes Sales Index rose 6.7 percent in June from June of last year. The housing market's collapse is at the heart of the longest U.S. recession since the Great Depression and reviving the sector is critical to healing the economy.

The Pending Home Sales Index in the Northeast rose 0.4 percent to 81.2 in June and was 5.8 percent above the same period last year. In the Midwest, the index climbed 0.8 percent to 89.9. It was 11.6 percent higher than June 2008.

The index in the South jumped 7.1 percent to 100.7 in June and was 8.9 percent higher versus a year ago. In the West, the index rose 2.9 percent to 100.4, but was 0.2 percent below June 2008.

(Reporting by Lucia Mutikani; Editing by Neil Stempleman)