Recognising that there are many pressing challenges in the Middle East, US Secretary of State Rex Tillerson has said, defeating the Islamic State terror group is Washington's number one goal. He was addressing the 10th meeting of the 68-member Global Coalition against IS. <br/><br/>Mr. Tillerson said, the group is united in stopping the IS resurgence, halting its global ambitions, and discrediting its ideological narrative. It was the first full meeting of the coalition since 2014.