NEW YORK (AP) - Angel Has Fallen easily topped the box office with a US$21.3 million (S$32.1 million) debut, as the action sequel became the latest mid-budget release to find modest success in the often quiet late summer.

The film beat expectations going into the weekend, opening similarly to the previous 2016 instalment London Has Fallen.

The film series stars Gerard Butler as a Secret Service agent protecting the American president played by Morgan Freeman.

Going back to 2013's Olympus Has Fallen, the franchise has been a quietly consistent performer, taking in roughly US$200 million worldwide each time.

Late August is known as a sleepy period at the box office, but is also one of the few parts of the calendar relatively light on big-budget tentpole releases.

That has given some room for recent successes such as Good Boys, which slid to second spot with US$11.8 million.

Last week, it became the first R-rated comedy in more than three years to land at No.1.

Scary Stories To Tell In The Dark has also flourished in August, taking in US$50.5 million in three weeks.

Some of the bigger films are still expanding around the globe, though.

The Fast & Furious spin-off Hobbs & Shaw opened over the weekend in China - where the high-octane franchise has regularly thrived - grossing US$102 million and pushing the film to a worldwide total of US$588.9 million.