LOS ANGELES (AFP) - Transformers: Age of Extinction extended its North American box office dominance into a second straight week, industry estimates showed on Sunday, earning US$36.4 million (S$45.3 million) over the Independence Day weekend.

The massive morphing robots epic - the first movie of the year to open with US$100 million on the domestic front - has earned US$174.7 million over two weeks, according to industry monitor Exhibitor Relations.

In second place was Tammy starring comedian Melissa McCarthy, whose road trip with her alcoholic grandmother, played by Susan Sarandon, debuted with US$21.2 million in ticket sales.

Third was another newcomer, the horror flick Deliver Us From Evil, with US$9.5 million in estimated ticket sales.

Buddy comedy 22 Jump Street, featuring Jonah Hill and Channing Tatum, pulled in US$9.4 million for fourth place.

Another blockbuster summer sequel, How To Train Your Dragon 2, came in fifth with US$8.75 million this weekend.

Family-friendly sci-fi Earth To Echo was in sixth place with US$8.25 million in earnings in its debut.

Angelina Jolie's Maleficent, a modern retelling of the life of Sleeping Beauty's arch-nemesis, grossed US$6.1 million for the weekend for seventh place.

Jersey Boys, Clint Eastwood's film adaptation of the hit Broadway musical about the 1960s rise to pop success of Frankie Valli and the Four Seasons, was in eighth place at US$5.2 million.

Comedy sequel Think Like A Man Too earned ninth place with US$4.9 million, while Tom Cruise action flick Edge of Tomorrow was 10th with US$3.6 million.