SEOUL, South Korea (AP) — Salvage crews in South Korea on Tuesday found bones and shoes believed to be from missing victims of a 2014 ferry disaster that killed 304 people, an official said.

The unexpected discovery, however, triggered an angry reaction from the missing victims' relatives, who criticized the government's salvage operation as poorly planned and questioned whether other remains might have gotten lost while workers raised the sunken ship last week.

Workers have just completed a massive operation to lift the corroding 6,800-ton Sewol from the sea, and recovering the remains of the nine missing victims would put the country a step closer to finding closure to one its deadliest maritime disasters.

Rescue workers had recovered the bodies of 295 people — most of them students on a high school trip — before the government ended underwater searches in November 2014, seven months after the ship sank. Nine of the ferry's passengers had remained missing.

On Tuesday, crews found six bones near a beam beneath the front side of the ferry, which had been loaded onto a heavy lift transport vessel that will carry it to port, said Lee Cheoljo, an official from the Ministry of Oceans and Fisheries.

It wasn't immediately clear whether the bones, measuring from 4 to 18 centimeters (1.5 to 7 inches), belonged to one person or multiple people, said Lee, adding that DNA tests to identify the victims would take at least two to three weeks. Crews also found shoes and other items that were presumed to have belonged to victims.

"It's presumed that the bones came out with the mud that spilled out from the ship's front," said Lee, adding that the bones might have come out from the ship's A-deck, where passenger cabins were.

He said crews suspended operations to empty the ferry of fuel and water and remove buoyancy equipment after the bones were discovered at around 11:25 a.m.

Crews on the transport vessel have drilled dozens of holes in the ferry in an effort to empty it of water and fuel before it's ready to be transported to a port in the city of Mokpo. Relatives had expressed concerns that remains of the missing victims could slip out through the holes and get lost.

A group representing the families issued a statement calling for the government to take stronger action to prevent the remains from getting lost during the salvage operations. They also called for the government to immediately search the mud the ferry has so far emitted, as well as the seabed where it was lifted from.

"It's now hard to discount the possibility that the (remains of the victims) could have gotten lost while the Sewol was being lifted from the seafloor and loaded onto the semi-submersible transport vessel," the group said. "It's hard to withhold our feeling of devastation."

Earlier Tuesday, relatives of the missing passengers participated in an emotional memorial service on a boat near the transport vessel, with representatives of Catholic and Protestant churches and Buddhists delivering prayers wishing for the remains of the nine to be recovered.

Relatives threw into the sea yellow roses, a color that has become the symbol of their suffering, and watched from afar as crews on the transport vessel continued to empty the ferry of water and fuel.

"The ship has come up, but not the nine people inside it," Lee Geum-hee, the mother of a missing schoolgirl, told a television crew. "Please don't forget there are people inside the dirty, rusty and smelly wreckage. ... Please do the best and let us bring them back home."

Once the ferry reaches a port in the city of Mokpo, investigators will spend about a month cleaning it and evaluating it for safety. They will then begin to search the vessel for the remains of the missing victims and look for clues that could further illuminate the cause of the sinking, which has been blamed on overloaded cargo, improper storage and other negligence.