Box office: 'Captain America: Civil War' battling to more than $75 million-plus Friday

Disney and Marvel's Captain America: Civil War is poised to post an opening day of more than $75 million, possibly approaching $80 million, as its kicks off the summerat the U.S. box office today, according to early estimates. That number includes the muscular $25 million in attracted in late-night showings on Thursday.

Civil War's preview gross was slightly behind that of last May's Avengers: Age of Ultron, which took in $27.6 million in previews, rang up a $84.4 million Friday and a first-weekend tally of 191.3 million. And it appears that Civil War could be chasing Ultron's numbers this weekend. Conservative estimates have the new Avengers movie heading for a $175-180 million weekend, although it could ultimately move closer to Ultron territory.

By weekend's end, the movie should rank third in term's of top May openings, behind Marvel's Avengers' $207.4 million in 2012 and Avengers: Age of Ultron's $191.3 million, but ahead of 2013's Iron Man 3, which collected $174.1 million.

Civil War set at least one record, though, Thursday, earning $3.1 million at its IMAX showings, a new Marvel record, bestingUltron's $3 million.

Civil War, which centers on a disagreement that forces the Avengers to choose sides between Captain America/Steve Rogers (Chris Evans) and Iron Man/Tony Stark (Robert Downey Jr.), is expected to have a much bigger domestic debut than the other Captain America films as this one includes many of the other Avengers stars, including Downey Jr., Scarlett Johansson, Anthony Mackie and Jeremy Renner. Plus, new additions to the Marvel cinematic universe Black Panther (Chadwick Boseman) and Spider-Man/Peter Parker (Tom Holland) make their debuts.

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The previous Captain America film, Winter Soldier, took in $10.2 million on Thursday night when it opened in April 2014. It earned $714.4 million worldwide.

Civil War is also expected to become one of the top five openings of all time domestically, joining an elite club alongside Star Wars: The Force Awakens ($248 million), Jurassic World ($208.8 million), The Avengers ($207.4 million), Avengers: Age of Ultron ($191.3 million) and Iron Man 3 ($174 million).

Anthony and Joe Russo's superhero film, which sees Captain America trying to protect his friend Bucky Barnes (Sebastian Stan) while dealing with the rift between him and Stark, began rolling out in foreign markets this past weekend, earning a massive $291.2 million overseas to date. That doesn't include China, where it is set to open day-and-date with the U.S.

Captain America: Civil War opened in Argentina Thursday where it earned an estimated $0.7 million and in Russia where it earned $2.6 million, pacing ahead of Avengers: Age of Ultron. The New Zealand opening yesterday came in at an estimated $0.5M, just ahead of Avengers: Age of Ultron.

May 6, 1 pm Updated to include Friday estimates.