Russia and China have vetoed a UN resolution calling for sanctions to be imposed on Zimbabwe. The US-authored resolution would have imposed an assets freeze and a travel ban on Robert Mugabe, the president, and 13 of his closest allies, as well as an arms embargo on the country. Russia and China, two of the five permanent members of the UN security council, joined South Africa, Libya and Vietnam in opposing the measures on Friday. Do you think sanctions should be imposed on Zimbabwe?