Turkish President Recep Tayyip Erdogan on Wednesday urged Washington would "reverse" its decision to arm a Syrian offshoot of the Kurdistan Workers' Party (PKK) before his visit to the US next week.Speaking on a joint press conference with Sierra Leone President Ernest Bai Koroma in Ankara, Erdogan said, "A terrorist group cannot be defeated with another one," Xinhua citing private broadcaster NTV as saying."Everything that happens in Syria and Iraq is a matter of national security for Turkey," he stated.The president said he would express his concerns in this regard at the meeting with his US counterpart Donald Trump on May 16, adding the same issue would also be brought up at the NATO summit to be held in Brussels on May 25.