"I think the reaction is an understandable one," said Straw in London, after Russian army chief of staff Yury Baluyevsky said Moscow would not hesitate to carry out pre-emptive strikes to "liquidate terror bases in any region".

"The United Nations charter does give the right of self-defence and the UN itself has accepted that an imminent or likely threat of terrorism certainly entitles any state to take appropriate action," Straw said.