Russian President Vladimir Putin gave an order to the Federal Security Service to strengthen protection of the country's border with class="mandelbrot_refrag"> Ukraine to prevent people crossing illegally, Russian news agencies reported on Saturday. _0"> The order comes a day after Putin held talks with global leaders in class="mandelbrot_refrag"> France , where U.S. President class="mandelbrot_refrag"> Barack Obama called on him to cease support for separatists in eastern class="mandelbrot_refrag"> Ukraine and stop the provision of arms and material across the border. (Reporting by Lidia Kelly; Editing by Mark Trevelyan )