president. >> reporter: as a golf course, they gathered for a summit. the fighting in northern syria dominated their private conversation, between u.s. and russian leaders, there were common goals, but little meeting of the minds. >> we do have differing perspectives on the problem, but we share an interest in reducing the violence, securing chemical weapons, ensuring they're neither used nor subject to proliferation. >> reporter: british prime minister saying bashar al-assad has to go, vladimir putin vowed not to let the rebels replace him. >> translator: i believe one does not need...