China, Russia and Iran will hold joint naval drills starting Friday in the Gulf of Oman, Beijing and Tehran said, at a time of heightened tensions since the U.S. withdrew from a landmark nuclear deal with Tehran. The military exercises aim to “deepen exchange and cooperation between the navies of the three countries. Chinese navy would deploy its Xining guided missile destroyer — nicknamed the “carrier killer” for its array of anti-ship and land attack cruise missiles — in the drills. For Iran, the drill’s purpose was to bolster “international commerce security in the region” and “fighting terrorism and piracy,”