This post will be updated as news comes in.

A second day of dangerous efforts to reach any survivors has ended with still no sign of the nearly 300 people — most of them high school students — believed to be trapped aboard a South Korean ferry that has capsized in the Yellow Sea.

South Korean coast guard authorities said Thursday that divers have not been able to get into any of the cabins aboard the overturned ship, the Sewol. Bad weather and rough seas are said to be hampering the search efforts. South Korea's Yonhap News Agency reports that "diving operations were suspended altogether around 1 p.m. [Thursday, local time] due to bad weather, officials said." South Korea is 13 hours ahead of the eastern U.S.

Meanwhile, it's not yet clear what caused the disaster, NPR's Anthony Kuhn reports from the South Korean port of Jindo. Survivors have said they heard and felt a loud bang early Wednesday (local time) just before the ship began to list. The ship also may have deviated from its usual course, which raises the possibility that it hit something that wasn't on navigation charts. Yonhap News writes that Koh Myung-seok, a senior coast guard official, told reporters that the ferry "took a path slightly different from the route recommended by the Ministry of Maritime Affairs and Fisheries."

There are more reports, similar to those first heard on Wednesday, about a delay in the order to abandon ship that may have contributed to the large number of passengers who didn't make their way to safety. Survivors are telling of orders they were given to don life jackets — but to also remain in place:

"The first instructions from the captain were for the passengers to put on life jackets and stay put, and it was not until about 30 minutes later that [the captain] ordered an evacuation, Oh Yong-seok, a 58-year-old crew member, told The Associated Press. The loss of that precious half-hour may have deprived many passengers of the opportunity to escape as The Sewol sank on Wednesday, not too far from the southern city of Mokpo."

The captain is among those who survived. According to the AP, he has spoken to reporters:

" 'I am really sorry and deeply ashamed,' a man identified by broadcaster YTN and Yonhap news agency as the captain, 60-year-old Lee Joon-seok, said in brief comments shown on TV, his face hidden beneath a gray hoodie. 'I don't know what to say.' "

As we reported Wednesday, the Sewol departed from the city of Incheon, South Korea, Tuesday night (local time) for what was supposed to be a 12- to 13-hour voyage south to the resort island of Jeju.

According to authorities, there were 475 people aboard the ferry, which can carry more than 900 passengers. Of those on board, 325 are said to have been high school students from the city of Ansan, near Seoul. They were on a school trip.

As of early Friday in Korea, officials were saying:

-- 25 bodies had been recovered.

-- 179 people had been rescued.

-- About 270 people were still missing.

Those figures will likely change. We will update as they do. (The numbers changed at 6:50 p.m. ET with AP's report of 25 bodies recovered, up from nine earlier.)

According to Yonhap News, officials say 169 boats and 29 aircraft are taking part in the rescue effort. And: "two salvage cranes are also on their way to the scene to raise the sunken vessel, with one of them expected to arrive on Friday morning and the other in the evening."

The water at the disaster site "is relatively shallow at under 165 feet," Reuters reports. (Update on the water's depth added at 10 a.m. ET.)

President Obama on Thursday expressed his condolences for the families of victims. He said the United States has an "unwavering commitment" to South Korea in good times and bad.

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