SAN DIEGO (AP) -Strong safety Clinton Hart agreed to terms on a new five-year contract Monday that will keep him with the San Diego Chargers through the 2012 season.

Hart, who reached the NFL after playing in the Arena Football League, was a full-time starter for the first time in 2007 and was San Diego's third-leading tackler with 109. He had five interceptions.

``We believe his best football is ahead of him,'' general manager A.J. Smith said in a statement released by the team.

Hart was scheduled to become an unrestricted free agent following the 2008 season.

``It's a day that I've been waiting for,'' Hart said. ``I've put in a lot of work. I feel blessed and I'm happy to be part of the Chargers for a few more years so we can make that run at a world championship.''

Hart, who didn't play college football, joined the Chargers in September 2004 after he was claimed off waivers from the Philadelphia Eagles. In five NFL seasons, he's made 31 starts in 78 regular-season games.