(VOVworld) – US Defense Secretary Chuck Hagel admitted on Saturday that the fight against IS militants will be difficult and prolonged. The statement was made in the context of increasing air strikes by the US-led international coalition to chase away IS militants from Syria’s Kobani town. The US Defense Secretary said international efforts have achieved a number of victories in the anti-IS fight. He said that Iraqi security forces are in full control of Baghdad but the Kobani city in Syria remains a big problem, adding that air strikes have progressed in repelling IS militants. He said that the fight against IS will require long-term efforts and pledged to continue helping Iraq with air strikes, aid and advisors.