evidence: Vietnam hotly disputes China's historical account, saying China had never claimed sovereignty over the islands before the 1940s. Vietnam says it has actively ruled over both the Paracels and the Spratlys since the 17th Century - and has the documents to prove it. [...] In 1974, the Chinese seized the Paracels from Vietnam, killing more than 70 Vietnamese troops. [...] In May 2014, the introduction by China of a drilling rig into waters near the Paracel Islands led to multiple collisions between Vietnamese and Chinese ships.