ANKARA, March 14 (Reuters) - Turkish President Tayyip Erdogan on Wednesday threatened to soon crush militants in northern Iraq, after his foreign minister last week said Ankara and Baghdad would carry out a joint offensive against Kurdish militants in Iraq. "We are checking the terror nests in northern Iraq at every chance. Soon, we will stomp very strongly on the terrorists there," Erdogan told local administrators in Ankara. Foreign Minister Mevlut Cavusoglu said last week that Turkey and Iraq's central government could start a joint military operation against Kurdish militants after Iraqi parliamentary elections scheduled for May 2018. Turkish warplanes regularly launch strikes against the outlawed Kurdistan Workers Party (PKK), which has camps in the mountains of northern Iraq, near the border with Turkey.