Iron Man 3 has scored the second highest-grossing opening weekend in U.S. history.

The sequel has crushed the competition around the world, and now it has soared to the top of the American box office with a staggering $175.3 million (Gbp110 million) three-day total.

That means Robert Downey, Jr. and Marvel Studios have the top two opening-weekend box office killers - last year's (12) The Avengers is the only film to have debuted with better figures - it remains the only movie to hit number one with more than $200 million (Gbp125 million) in the U.S.

Last week (ends03May13), Iron Man 3 landed the biggest opening day ever in China and became the biggest April release ever in Italy.

The third installment in the blockbuster Marvel franchise has now earned over $600 million (Gbp375 million) at the global box office.