The London Olympics are considered a prime target for terrorists and protecting the dignitaries and athletes who will attend could be too big a strain for British police, most of whom are not trained to use guns.
Police Commissioner Sir Ian Blair told a Metropolitan Police Authority meeting on Thursday that it may be very expensive to give firearms training to the number of protection officers needed during the Olympics.
"The principle must be that we don't want armed foreign police," Blair said at the meeting, according to excerpts of his comments provided by police.
However, Blair said he has been evaluating "the number of protected persons and whether we actually have, in the United Kingdom, sufficient capacity to actually have enough armed officers to do the job ... So there are some real dilemmas."
Blair said within the next year police officials will have to decide whether police from outside Britain should be brought in as a last resort to guard dignitaries.
Only about 6,500 of more than 143,000 police officers in England and Wales are authorized to carry guns.
A total of 600 million pounds (US$1.2 billion; 880 million EUR) has been earmarked for security during the Olympics from the games' total budget of 9.3 billion pounds (US$18 billion; 13.7 billion EUR).