Maxis' SimCity revival launched in the US yesterday, but some American gamers have been left unable to play due to the game's servers collapsing because of "overwhelming demand."

SimCity requires an always-on Internet connection, alongside an account on EA's digital distribution platform Origin. Over the past 24 hours, users have reported problems both in accessing the game's servers and in even being able to download the game to begin with.

"Due to the high demand for SimCity, Origin has experienced delays impacting a small percentage of users. We're working non-stop to resolve," wrote the Origin Twitter account overnight.

In the meantime, Origin has said it is confident that the same errors which plagued the US launch will not affect other territories when the game launches later this week. "We're making changes to prevent further issues, and are confident that Origin will be stable for international launches later this week," said Origin.

Maxis has consistently maintained that its always-on DRM for SimCity will be of benefit to the end user, with the game functioning as a connected experience designed to be played with others. "You're always connected to the neighbors in your region so while you play, data from your city interacts with our servers, and we run the simulation at a regional scale," said Maxis senior vice president Lucy Bradshaw in December 2012.

SimCity is the latest high-profile title to suffer with connectivity issues at launch. Diablo 3 was notably troubled with issues when it launched last year, but popular online titles like Battlefield 3 often have their multiplayer servers buckle at launch.

SimCity launches in the UK on Friday. A GameSpot review is currently in the works.