JINDO, South Korea » South Korea’s president apologized Tuesday for the government’s inept initial response to a deadly ferry sinking as divers fought strong currents in their search for more than 100 passengers still missing nearly two weeks after the accident.

The government also raised the death toll for what has become a point of national mourning and shame to 193. Most of the dead and missing are high school students.

Divers are largely using their hands to feel for remaining bodies as they make their way through a maze of dark cabins, stairwells, storage rooms, lounges and restaurants in the submerged ferry, which flipped upside down as it sank April 16. But they must fight strong currents swirling around the ferry and, once inside, overturned furniture, mattresses and other debris floating in the murky, sediment-heavy waters.

President Park Geun-hye’s apology, and the earlier resignation of her prime minister, comes amid rising indignation over claims by the victims’ relatives that the government did not do enough to rescue or protect their loved ones.

Park said at a cabinet meeting at the presidential Blue House that South Korea has "lost many precious lives because of the accident, and I am sorry to the public and am heavy-hearted." She says the government couldn’t prevent the accident and "the initial response and remedy were insufficient."

Park had earlier visited a memorial set up in Ansan, the city near Seoul where the high school students are from, to pay her respects to victims. Wearing a black dress and white gloves, she laid flowers at an altar and bowed her head. According to local media, some angry family members of victims shouted at her and demanded an apology. She listened to them for 10 minutes before leaving.

Investigators, meanwhile, are expanding their probe into both the cause of the ship’s sinking and the initial response by emergency workers. Officials have searched the two service centers that deal with vessel traffic and that communicated with a crew member on the ferry during the sinking, seized documents and recordings from a coast guard office in Mokpo, and have continued questioning the captain, the third mate and the helmsman who were on the bridge when the ship began listing.

Only 174 people survived the sinking, including 22 of the 29 crew members.

The government is making initial plans to eventually salvage the ferry but has indicated it won’t do so until search efforts end.

All 15 crew members responsible for the ship’s navigation have been arrested, but they haven’t been formally charged yet because investigations are still going on.

The arrested crew members are accused of negligence and of failing to help passengers in need. Capt. Lee Joon-seok initially told passengers to stay in their rooms and took half an hour to issue an evacuation order, by which time the ship was tilting too severely for many people to get out. Lee told reporters after his arrest that he withheld the evacuation order because rescuers had yet to arrive and he feared for passengers’ safety in the cold, swift water.

The ferry was carrying an estimated 3,608 tons of cargo, according to an executive of the company that loaded it. That far exceeds what the captain claimed in paperwork — 150 cars and 657 tons of other cargo, according to the coast guard — and is more than three times what an inspector who examined the vessel during a redesign last year said it could safely carry.

Senior prosecutor Yang Jung-jin said that the cause of the sinking could be due to excessive veering, improper stowage of cargo, modifications made to the ship and tidal influence. He said investigators would determine the cause by consulting with experts and using simulations.

Lee reported from Mokpo, South Korea. Associated Press writers Jung-yoon Choi and Foster Klug in Seoul contributed to this report.