The Archbishop of York, Dr John Sentamu, who was making his first public appearance since he revealed he had prostate cancer, has described the idea of arming the Syrian rebels as "very, very naive."
"There are all kinds of very different factions and it may simply be a battle between Shiites and Sunnis, but also a battle within among themselves - the radicals, the conservatives, the reformists. It's a toxic mixture," he told BBC Radio 5 Live's Pienaar's Politics.
Dr Sentamu also criticised corrupt government officials who embezzle funds from the public purse, at an ecumenical service in Enniskillen, Northern Ireland, ahead of the G8 summit.
"They are directly robbing the poor of their education, health, food, employment and sustainable development," he said.
"We say, from this fantastic cathedral to both types of robbers, 'enough is enough. Stop indirectly and directly robbing the poor'."
David Cameron admitted there were 'big differences' between the UK and Russia on the Syria conflict, but insisted they could be overcome
Russia warned the West that arming Syrian rebels could escalate violence as David Cameron backed a US assessment of a need for involvement.