The United States and Britain called on Wednesday for political action to end violence in Kenya as the death toll rose to more than 300 in clashes between supporters of President Mwai Kibaki and opposition leader Raila Odinga, according to a state-funded local rights organisation and an international group.

“The immediate priority is to combine a sustained call from Kenya’s political leaders for the cessation of violence by their followers,” said Condoleezza Rice, the US secretary of state, and David Miliband, the UK foreign minister, in a joint statement.