Nicolas Cage in 'World Trade Center' from Paramount Pictures. Director Oliver Stone's film on the September 11 World Trade Center attack opened to tears and torment in the United States on Wednesday, reviving memories ahead of the fifth anniversary. (Handout/Reuters)

Oliver Stone's new film, "World Trade Center," got off to a promising start at the box office on Wednesday, grossing better-than-expected receipts of $4.4 million in its first day, Paramount Pictures executives said on Thursday.

They added that if the pace continued, the film about the battle to save two policemen trapped under tons of rubble in the September 11 attacks could bring in more than $20 million through its opening weekend -- a figure that would exceed expectations.

The $65 million movie, which received several strong reviews, is the first big-budget feature to be made about the suicide hijackings, although a smaller budget film "United 93" last spring grossed $31.5 million.

Many industry experts questioned whether moviegoers are ready for films about the disaster which is still fresh and painful in the minds of many Americans.