Infinity Ward has revealed that its Xbox Live-topping shooter Call of Duty 4 is attracting "between 1.2 and 1.3 million users every day" just on Microsoft's service - with PS3 numbers "monstrously huge".

Speaking to Eurogamer in London last week during the unveiling of the new downloadable maps for the game, producer Mark Rubin revealed that Infinity Ward had been hitting these figures "consistently for the past two-to-three months, Monday through Sunday. It's crazy."

He added: "That's just 360. There's even more on the other platforms [PS3 and PC], but we just don't have the same numbering system. Overall, even without the other consoles, we are beating the competition. PS3 numbers are monstrously huge. No other game has come close, either online current, or total unique users in a day."

The hugely popular contemporary update to the studio's previously WWII-focused war franchise has been fighting with Bungie's Halo 3 for the top spot on the Xbox Live rankings since its release, but has pulled clear in recent months. Speaking on the rivalry, Rubin commented:

"We've created a lot of heartache for a lot of companies who go up against it. I think Halo's website says they get something around 845,000 to a million [per day]."

Call of Duty is understood to have sold over 7 million units so far. While Rubin refused to confirm the percentage of online users, he admitted it had exceeded expectations:

"I don't have an exact number for you, but it turns out to be a startling number of people. For a lot this is there first time playing a multiplayer game on console or PC. We're getting really high numbers."

The Variety Map Pack for Call of Duty 4 is due for release in April. You can read the full interview with Rubin here.