Screen Gems' horror film Prom Night had too much in the tank as it launched at number one on approximately $22.7m, some $11m ahead of Fox Searchlight's new police thriller Street Kings in second place.

However the box office slide continued as the top 12 releases combined for $82.6m, down 16% from the same weekend last year. All eyes inevitably turn to May 2, when Iron Man will kick off the summer blockbuster season.

Prom Night combines the proven elements of a sadistic stalker and a pretty high school student and stars Brittany Snow, Scott Porter and Jessica Stroup.

Keanu Reeves plays a world-weary cop in Street Kings, which debuted on $12m; it also stars Forest Whitaker, Chris Evans, Hugh Laurie and Cedric The Entertainer.

The only other new entry in the top 10 was Smart People, a drama about a widowed professor whose life is turned upside-down by the arrival of his adopted brother. It opened through Miramax in seventh place on $4.2m and stars Dennis Quaid, Sarah Jessica Parker, Thomas Haden Church and Ellen Page.

Elsewhere the usual suspects each shifted a couple of places down the table. Nim's Island ranks fourth on $25.3m after two, Leatherheads is fifth on $21.9m after two and Horton Hears A Who in sixth place stands at $139.6m after five.

Overture's acquisition The Visitor launched outside the top 20 on $88,000 from four theatres. Richard Jenkins plays a college professor who strikes up a friendship with Syrian and Senegalese immigrants whom he discovers living illegally in his apartment.

Focus Features' Miss Pettigrew Lives For A Day added $509,829 from 471 theatres for $11.3m. Sundance opener In Bruges grossed $183,648 from 163 and stands at $7.1m.

Next weekend's wide releases are The Weinstein Company and Lionsgate's martial arts extravaganza The Forbidden Kingdom with Jackie Chan and Jet Li; Sony's thriller 88 Minutes starring Al Pacino; and Universal's comedy Forgetting Sarah Marshall, produced by Judd Apatow.

Estimated Top 10 North America Apr 11-13, 2008
Film (Dist)/Int'l dist/Est wkd gross/Est total to date

1 (-) Prom Night (Screen Gems) SPRI $22.7m -
2 (-) Street Kings (Fox Searchlight) Fox Int'l/Regency $12m -
3 (1) 21 (Sony) SPRI $11m $62.3m
4 (2) Nim's Island (Fox) Summit Entertainment $9m $25.3m
5 (3) Leatherheads (Universal) UPI $6.2m $21.9m
6 (4) Dr Seuss' Horton Hears a Who! (Fox) Fox Int'l $6m $139.6m
7 (-) Smart People (Miramax) QED Int'l $4.2m -
8 (5) The Ruins (Paramount) PPI $3.3m $13.4m
9 (6) Superhero Movie (MGM) TWC $3.1m $21.2m
10 (8) Drillbit Taylor (Paramount) PPI $2.1m $28.5m