Russian President Vladimir Putin has criticized the U.S. decision to arm Syrian rebels following a meeting with British Prime Minister David Cameron in London.

David Cameron said the two leaders have very big differences in their analyses of what is happening in Syria and who is to blame.

"With regards to supplying weapons to the Assad government and with regards to who has the blood of children and that of peaceful Syrian citizens on their hands, I believe you cannot deny that blood is on the hands of both parties. There is always a question who is to blame? I believe one does not really need to support the people who not only kill their enemies, but open up their bodies, eat their intestines in front of the public gaze and cameras. Are these the people you want to support? Are they the ones you want to supply with weapons?

Putin was referring to video footage posted to the internet of a rebel fighter eating what appeared to be the heart of a government soldier.

Cameron acknowledged differences but said he was hopeful about the talks.

Britain has not said whether it join the U.S. in arming rebels. The meeting between the two came just a day before world leaders arrive in Northern Ireland for the G8 Summit today.