The Dark Knight stayed on top for the third consecutive weekend, edging out The Mummy: Tomb Of The Dragon Emperor as it bears down on $400m in record time. Warner Bros' champion added an estimated $43.8m for $394.9m in what was the second biggest third weekend in history behind Spider-Man's $45m set in 2002.

The crime epic should cross $400m on Monday in a record 17 days that will pulverise the old mark of 43 set by Shrek 2 in 2004. For the record, The Dark Knight was also the fastest to $350m in 14 days and now holds the speed records for every $50m increment up to $350m so far.

Universal's third episode in The Mummy franchise - and the first entry in the series in seven years - launched over three days on $42.56m. Brendan Fraser reprises his role as the adventurer Rick O'Connell alongside cast regular John Hannah and new additions Jet Li, Michelle Yeoh, Mario Bello, Isabella Leong and Luke Ford.

The Mummy got off to a flying start on Friday with $15.4m compared to The Dark Knight's $12.7m, however by Saturday and Sunday it had slipped to $14.8m and $12.3m as its rival managed $17.4m and $13.7m.

Buena Vista's light comedy Swing Vote, which stars Kevin Costner as a politically detached Midwesterner who holds the casting vote in the Presidential Election, opened in sixth place on $6.3m. Buena Vista/Pixar's Wall-E crossed $200m in its sixth weekend and ranks eighth after adding $4.7m for $204.2m.

Sony's comedy Step Brothers fell one place to third on $16.3m for $62.9m after two weekends while Universal's musical Mamma Mia! ranks fourth on $13.1m for $87.9m after three and New Line's Journey To The Center Of The Earth is fifth after four on $6.9m for $73.1m.

Music Box' French thriller Tell No One added $314,637 from 88 screens for $2.3m after five weekends.

Next weekend's wide releases are Sony's comedy Pineapple Express starring Seth Rogen, James Franco and Danny McBride and Warner Bros' drama Sisterhood Of The Traveling Pants 2 with America Ferrera, Blake Lively, Amber Tamblyn and Alexis Bledel.

Estimated Top 10 North America Aug 1-3, 2008
Film (Dist)/Int'l dist/Est wkd gross/Est total to date

1 (1) The Dark Knight (Warner Bros) WBPI $43.8m $394.9m
2 (-) The Mummy: Tomb Of The Dragon Emperor (Universal) UPI $42.5m -
3 (2) Step Brothers (Sony) SPRI $16.3m $62.9m
4 (3) Mamma Mia! (Universal) UPI $13.1m $87.9m
5 (5) Journey To The Centre Of The Earth (New Line) NLI $6.9m $73.1m
6 (-) Swing Vote (Buena Vista) Kathy Morgan Int'l $6.3m -
7 (6) Hancock (Sony) SPRI $5.2m $215.9m
8 (7) Wall-E (Buena Vista) WDSMPI $4.7m $204.2m
9 (4) The X-Files: I Want To Believe (Fox) Fox Int'l $3.4m $17.1m
10 (9) Space Chimps (Fox) Fox Int'l/Various $2.8m $22.1m