Mel Gibson thriller Signs has spent another week at the top of the North American box office, taking $16.5m (�10.4m) over the extended US Labor Day weekend.

Signs, about a clergyman whose family is plagued by mysterious crop circles, is well on the way to topping the $200m (�131m) mark after a month on release, making it one of the biggest hits of the summer.

The film topped the charts in its first week on release in the US and Canada before being knocked from the top spot by the action thriller XXX, starring Vin Diesel.

US/Canada Top 10

1 Signs: $16.5m 2 My Big Fat Greek Wedding: $14.6m 3 XXX: $13.1m 4 Spy Kids 2: $7.3m 5 feardotcom: $7.1m 6 Goldmember: $7.1m 7 Blue Crush: $5.4m 8 Serving Sara: $4.2m 9 The Good Girl: $3.6m 10 One Hour Photo $3.3m Source: Exhibitor Relations

However, it regained pole position last week as the summer blockbuster season began to wind down, with fewer high-profile films being released. It is released in the UK on 13 September.

Second place on the charts went to the low-budget comedy My Big Fat Greek Wedding, which had its biggest weekend yet, making $14.6m (�9.5m).

The film, about a girl from a Greek family trying to win her parents' approval of her non-Greek fiance, was released in North America in April and has crept steadily up the box office chart throughout the summer.

So far, it has made $82.3m (�54.1m), and is on course to make over $100m (�65.7m) - which would make it one of the most profitable films of the summer, given its low budget.

My Big Fat Greek Wedding was released four months ago

"Some of us were talking at the beginning about $20m or $25m if we're lucky, but no-one ever dreamed of hitting $100m," said Rob Schwartz, president of IFC Films, who released Greek Wedding.

It opens in the UK on 20 September.

Only one new release, the horror film feardotcom, made it into the charts this week, reaching number five with a total of $7.1m (�4.6m).

The film about a string of murders linked to a mysterious website, has received some of the year's worst reviews so far.

Meanwhile, Jennifer Aniston drama The Good Girl, and One Hour Photo, starring Robin Williams as a photo developer who becomes obsessed with one of his clients, both crept into the top ten.

Both films were released in only a small number of cinemas in the US initially, but have now been given wider releases after being well received by both critics and public.

Robin Williams stars in One Hour Photo

Next weekend Signs faces a challenge from two new releases, drama City By The Sea, starring Robert De Niro and Frances MacDormand, and teen thriller Swimfan.