'Avatar' rules box office for sixth weekend

LOS ANGELES Jan 24 (Reuters) - "Avatar" passed "The Dark Knight" to become the second-biggest movie of all time at the North American box office on Sunday, as it logged a sixth consecutive weekend in the top spot.

James Cameron's sci-fi spectacular earned $36 million during the three days beginning on Friday, taking its total to $552.8 million, distributor 20th Century Fox said.

The 2008 Batman sequel, "The Dark Knight," finished at $533 million. The only film ahead of "Avatar" is Cameron's "Titanic," which pulled in $601 million in 1998. Fox, a unit of News Corp (NWSA.O), said it expected "Avatar" to surpass "Titanic" in about two weeks. (Reporting by Dean Goodman; Editing by Paul Simao)