ANKARA (Reuters) - Turkish security forces killed more than 30 Kurdish militants in a cross-border operation overnight, President Tayyip Erdogan said on Tuesday. Turkey's mainly Kurdish southeast has been scorched by fighting between security forces and Kurdish militants since a ceasefire fell apart in July. Some critics say Erdogan has launched a crackdown to bolster nationalist support for the ruling AK Party before November elections. (Reporting by Orhan Coskun and Humeyra Pamuk; Writing by David Dolan; Editing by Andrew Heavens)