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Ahn Young-joon, Associated Press
Family members of the ferry victims attend a rally to commemorate the first anniversary of the Sewol ferry sinking in Seoul, South Korea, Thursday, April 16, 2015. Angry relatives of passengers who drowned in a ferry sinking snubbed South Korean President Park Geun-hye on the disaster’s one year anniversary Thursday even as she pledged to salvage the ship.

SEOUL, South Korea — With public anger and grief raw one year after a ferry sinking killed 304 people, South Korea's president promised on Thursday to raise the submerged vessel, even as relatives of the victims snubbed her appearance at a mourning ceremony.

Black-clad relatives and their supporters remembered the dead, most of whom were high school students, on the anniversary of the sinking of the Sewol in one of the country's worst maritime disasters.

Earlier in the day, relatives blocked the prime minister from attending a mourning event. They later canceled another ceremony because of what they called government indifference to their plight.

There's frustration among South Koreans who see their government as having failed to make meaningful improvements to safety standards and hold high-level officials accountable for a disaster blamed in part on incompetence and corruption.

Hours before a trip abroad, President Park Geun-hye visited a small port near the site of the sinking to offer condolences to bereaved relatives. Most, however, refused to meet her to protest the government's response.

Park gave a speech anyway, announcing plans to salvage the ferry — a demand of the relatives. She said only that the operation would happen "as soon as possible."

Flags at public buildings were lowered to half-staff and a minute of silence was observed in Ansan, the city that lost nearly an entire class of students on a doomed field trip to a southern resort island. A private ceremony was planned at Danwon High School in the evening.

Relatives canceled a memorial service in Ansan that thousands were planning to attend. They expressed anger over Park not visiting the site and not giving a firm commitment for a deeper investigation into what they say is government responsibility for the sinking and botched rescue.

The relatives also claimed that Park should have delivered a more detailed plan for salvaging the ship in her speech at the port, according to Pil Kyu Hwang, a lawyer representing the families.

The estimated cost of raising the ferry is between $91 million and $137 million, and it could take as long as 1½ years.

Relatives in Ansan wept and touched pictures of their lost loved ones as they recalled helplessly watching on television as the ferry slowly sank into the sea.

Scores at the port near the sunken ship walked to a lighthouse where hundreds of yellow ribbons were tied to handrails in memory of the victims.

Mourners including family members and students attended an evening rally in downtown Seoul, where relatives have protested for months. The group tried to march to the president's home but was blocked by police.

Earlier Thursday, lawmakers overwhelmingly approved a resolution urging the government to salvage the ferry.