Angry parents of victims of last week's Korean ferry disaster assaulted a top official today, accusing him of lying about efforts to retrieve bodies still trapped in the submerged ship.

About 20 relatives of the victims attacked Choi Sang-Hwan, deputy head of the Korea Coast Guard.

They stormed his temporary office at Jindo port, an AFP journalist at the scene said.  

Relatives forced their way through about ten officers blocking the entrance and punched Mr Choi in the face and body.

They then grabbed him by the neck and pulled him out of the office.

Ripping his shirt, they took him to a nearby tent calling for his superior Kim Suk-Kyun, the coast guard chief, to meet them there.

The parents held Mr Choi for a while, with some mothers slapping him continuously, until his superior arrived.

Parents then forced the coast guard chiefs to tell their officers by radio to mobilise more divers and speed up efforts to recover bodies.

There is widespread anger among families over the slowness of initial rescue efforts after the ferry sank on 16 April with 476 people on board, most of them high school students.

It took divers working in difficult and dangerous conditions more than two days to get into the sunken ferry and two more days to retrieve the first bodies.

The confirmed death toll today stood at 171, but 131 were still missing and believed inside the ship.

Violence broke out today after the relatives went out by boat to inspect operations at the site where the 6,825-tonne Sewol capsized.

"You guys said hundreds of divers were working there, but we only saw a few there today," a mother shouted at Mr Choi.

The parents demanded that closed-circuit TVs be set up for them to watch rescue efforts live.

Classes resume at school scarred by ferry disaster

Meanwhile, senior classes resumed today at the South Korean high school devastated by the loss of around 250 students in the ferry disaster.

The final-year students from Danwon High School in Ansan city, just south of Seoul, returned to their classrooms.

The classrooms have remained empty since the ferry capsized and sank.

Junior classes will start next Monday, a provincial education official said.

The official added that he was "unsure" when the surviving members of the 11th grade class, which was taken on the trip, would resume their studies.

Across the road from the school, thousands of people paid their respects for a second day at a special memorial to the student victims in an indoor sports stadium.

More than 12,000 mourners visited the memorial when it opened yesterday.