LOS ANGELES, USA (AP) — The Dark Knight Rises stayed atop the box office for the second straight weekend, making just over US$64 million. But it's lagging behind the staggering numbers of its predecessor, 2008's The Dark Knight.

The final piece in Christopher Nolan's Batman trilogy has now grossed more than US$289 million in its first 10 days in theatres. It dropped 60 per cent from its opening weekend of US$160.9 million.

By comparison, The Dark Knight took a 53 per cent drop in its second weekend with a gross of nearly US$75.2 million and a 10-day cumulative gross of US$313.8 million.

Dan Fellman, head of distribution for Warner Bros, declined to comment on the estimates again out of respect for the victims of the Aurora, Colorado, shooting that left 12 people dead and another 58 injured at a midnight showing of the film on opening night.

But people are still going to the movies, and they did so even last weekend, said Hollywood.com analyst Paul Dergarabedian. If anything hurt the numbers for all movies this weekend, he said, it was Friday night's opening ceremony of the 2012 Summer Olympics in London, which drew a record-setting 40.7 million viewers in the United States.

"For a film that opened as big as this did, considering the situation and what happened last weekend and all that, I would say this is a very strong showing," Dergarabedian said. "It's made almost $300 million in North America and its mid-week (attendance) is very strong. It made $19 million last Monday."

In second place this weekend was the animated family film Ice Age: Continental Drift, which is still going strong in its third week. It made $13.3 million for a domestic total of nearly $114.9 million. The fourth movie in the 20th Century Fox franchise features the voices of Ray Romano, Denis Leary and Queen Latifah.

Both of the new movies in wide release opened weakly. The 20th Century Fox comedy The Watch came in third place with $13 million. And Step Up Revolution — the fourth film in the dance franchise, which is set in Miami this time — opened at No 4 with $11.8 million. Richie Fay, Lionsgate's president of domestic distribution, said the number was a little disappointing because the studio expected it to end up in the mid-teens. But the core audience for the previous three Step Up films showed up: 63 per cent was female and 71 per cent was under age 24.

As for new movies in limited release, Fox Searchlight's Ruby Sparks grossed $151,881 in 13 theatres for a strong per-screen average of $11,683. Since its opening Wednesday, it has made $191,717. The romantic comedy from the directors of Little Miss Sunshine stars Paul Dano as a novelist with writer's block who creates his dream girl, played by Zoe Kazan, who also wrote the script.

And LD Entertainment's Killer Joe, the NC-17-rated crime thriller from director William Friedkin, made US$37,864 at three theatres in Manhattan for a $12,621 per-screen average. In his darkest performance yet, Matthew McConaughey plays a Dallas police detective with a side gig as a hit man. Emile Hirsch, Thomas Haden Church, Gina Gershon and Juno Temple co-star as the lowlifes who play crucial roles in this twisted plot.