Hundreds, including students, rescued after ferry sinks off South Korea, no deaths reported

South Korean rescue helicopters fly over a South Korean passenger ship, trying to rescue passengers from the ship in water off the southern coast in South Korea, Wednesday, April 16, 2014. A government office said the passenger ship carrying about 470 people have sent a distress call off the southern coast after it began tittering to one side. (AP Photo/Yonhap) KOREA OUT (The Associated Press)

South Korea coast guard police officers work to rescue passengers from a South Korean passenger ship, at Mokpo Coast Guard in Mokpo, south of Seoul, South Korea, Wednesday, April 16, 2014. A government office said the passenger ship carrying about 470 people has sent a distress call off the southern coast after it began leaning to one side. (AP Photo/Cho Keun-young, Yonhap) KOREA OUT (The Associated Press)

South Korean rescue helicopters fly over a South Korean passenger ship, trying to rescue passengers from the ship in water off the southern coast in South Korea, Wednesday, April 16, 2014. A government office said the passenger ship carrying about 470 people have sent a distress call off the southern coast after it began tittering to one side. (AP Photo/Yonhap) KOREA OUT (The Associated Press)

Dozens of rescue boats and helicopters are scrambling to save more than 470 people, including many high school students, caught on a ferry sinking off South Korea's southern coast, officials said. There are no immediate reports of causalities.

The ferry with 476 people including 325 high school students was sailing to the southern island of Jeju when it sent a distress call Wednesday morning as it began leaning to one side, according to Ministry of Security and Public Administration.

Park Hye-rang, a local coast guard officer, said by phone that 147 passengers had been rescued so far, but gave no further details.

Local media photographs showed the ship heavily tilted onto its side, partially submerged, as helicopters flew overhead and rescue vessels and a small boat covered with an orange tarp floated nearby.

The students are from a high school in Ansan city near Seoul and they were on their way to the Jeju island for a four-day trip, according to a relief team set up by Gyeonggi Province, which governs the city. The ship left Incheon port, just west of Seoul, on Tuesday evening, according to the state-run Busan Regional Maritime Affairs & Port Administration.

A total of 18 helicopters and 34 rescue boats have been sent to the area, Vice Minister Lee Gyeong-og told a televised news conference. He said President Park Geun-hye has ordered a through rescue operation to prevent any human casualties.