(Reuters) - Several people appear to have survived in an air pocket of a capsized South Korean ferry, the father of one of the school children aboard the boat told a Reuters reporter accompanying families out to the scene of the disaster on Thursday.

About 290 people are still missing out of 450 passengers on the Sewol ferry, which capsized in still-mysterious circumstances off the Korean peninsula on Wednesday in what could be the country's worst maritime accident in 20 years.

Many of the passengers were school children from one high school on the outskirts of Seoul.

"(The child) told me in the text message, 'I am alive, there are students alive, please save us quickly," the father said.

Coastguard and navy divers resumed searching on Thursday after the ferry capsized in sight of land on a trip from the port city of Incheon to the holiday island of Jeju, about 100 km (60 miles) south of the peninsula.

Grieving family members gathered early on Thursday on the quay of the coastal city of Jindo, huddled in blankets against the spring cold as efforts to find the missing went into a second day.

One parent, Park Yung-suk, told Reuters she had seen the body of her teenage daughter's teacher brought ashore earlier in the morning.

"If I could teach myself to dive, I would jump in the water and try to find my daughter," Park said as light rain fell.

So far 179 people have been rescued and six confirmed dead.

As coastguard officials arrived at Jindo on Thursday, waiting relatives jeered at them, shouting: "The weather's nice, why aren't you starting the rescue."