PARIS, Aug 16 (Reuters) - Islamist militants will seek to benefit from the turmoil in Afghanistan, said French President Emmanuel Macron on Monday, adding that France would do all it could to ensure Russia, the United States and Europe responded with a common purpose. Afghan cities fell in just days and on Monday civilians thronged Kabul"s international airport after President Ashraf Ghani fled, saying he wanted to avoid a bloodbath, and the Taliban seized the capital. read more "Afghanistan must not become the haven for terrorists that it once was," Macron said in a national address. "It is a challenge for peace and international stability, against a common enemy. We will do everything we can so that Russia, the United States and Europe can cooperate efficiently, because our interests are the same. "The United Nations" security council will have to come up with a common and united answer." There was a risk that a wave of migrants would sweep towards Europe, Macron said. France would continue to protect the most vulnerable and would play its part in an organised and fair international effort to share the burden, he added. France, Germany and some other European countries would take the initiative to build a "robust, united, and coordinated response" with the help of transit countries, Macron said. Reporting by Richard Lough, Writing by Benoit Van Overstraeten, Editing by Sudip Kar-Gupta and Alex Richardson Our Standards: The Thomson Reuters Trust Principles.