In what may further aggravate the crisis in Ukraine, the United States and France have warned Moscow of stringent economic and diplomatic measures if Russia does not withdraw its troops from Crimea in Ukraine. The threat came after a phone call between US President Barack Obama and the French President Francois Hollande late last week. The head of states insisted on the “Need for Russia to withdraw forces sent to Crimea since the end of February and to do everything to allow the deployment of international observers.”“If there’s a lack progress in this direction, new measures will be taken which would noticeably affect relations between the international community and Russia, which is in no-one’s interest,” he added. Meanwhile Russia has strengthened its position in Crimea.