Naomi Watts has starred in both Ring films

The film, which stars Naomi Watts, is a remake of a Japanese shocker about a series of deaths linked to a mysterious video tape.

Last week's number one, computer animated adventure Robots, fell to second place, taking $21.8m (�11.3m).

Another former chart-topper, Vin Diesel comedy The Pacifier, dropped to third.

The Disney film Ice Princess and Will Smith comedy Hitch completed the top five.

Surprise hit

The original Ring, which also starred Naomi Watts was released in 2002 and was a surprise hit, taking around $129m (�66.9m) at the US box office.

US/ CANADA BOX OFFICE 1) The Ring Two - $36m (�18.7m) 2) Robots (above) - $21.8m (�11.3m) 3) The Pacifier - $12.5m (�6.5m) 4) Ice Princess - $9.8m (�5.1m) 5) Hitch - $6.6m (�3.4m) Source: Exhibitor Relations

Both films are based on a series of novels by Japanese author Koji Suzuki.

A spokesman for its distributor DreamWorks said it expected the film to mirror the pattern of other horror sequels, which have tend to have big opening weekends followed by a steady drop at the box office.

"Sequels just don't play the same way. You have to expect a good drop," said Jim Tharp, the studio's head of distribution.

"Obviously, we would hope to get $100m (�51.8m) but we don't do any of those projections this early in the game."