Four Turkish police officers travelling in a vehicle in southeast Turkey were killed on Thursday when explosives believed to have been planted by Kurdish militants were detonated as they passed by, security sources told Reuters. The blast in Mardin province is the latest in a surge of near daily attacks against security forces by Kurdistan Workers' Party (PKK) militants since the collapse of a two year ceasefire in July. http://english.ahram.org.eg/News/139553.aspx