South Korea and the United States began a large-scale amphibious landing drill on Thursday amid heightened tensions on the peninsula. The Ssang Yong (double dragon) exercise involves more than 10,000 naval and marine troops from both countries. It is the largest joint marine drill between the two nations since 1993, and is taking place on the Southeastern coast of the peninsular until April 7, Yonhap news agency reported. North Korea's state-run Rodong Sinmun newspaper on Monday denounced the drill and a joint aerial training exercise, accusing Washington of raising tensions, Yonhap said. Pyongyang test-fired two missiles into the sea early Wednesday, reports said. The Ssang Yong drill includes 200 South Korean marines and 1,000 naval troops as well as 7,500 US marines and 2,000 navy personnel, Yonhap said. Also taking part are 22 Osprey tilt-rotor aircraft and CH-53 heavy-lift helicopters.