Al Jazeera's correspondent in London, Alan Fisher, said parallels have been drawn with kidnapping plots in Baghdad, but added "there's no suggestion [from police] that this plot went further at the moment then a kidnap".
Police searched 12 homes in the predominantly-Pakistani neighbourhood in the central England city.
Two Islamic book stores were also cordoned off.
The men were arrested on "suspicion of the commission, preparation or instigation of acts of terrorism".
David Shaw, assistant chief constable of West Midlands police, said: "This remains a dynamic, fluid operation and it is by no means finished. We are literally right at the foothills of what is a very, very major investigation for us."
Britain remains on its second-highest threat level of "severe" which indicates that security services believe a terrorist attack is highly likely.