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Christchurch, New Zealand (CNN) -- The death toll from the 6.3-magnitude earthquake that struck Christchurch this week has risen to 113, police said Friday morning.
More people are feared dead, and more than 200 are still missing, police said.
Police Superintendent Dave Cliff told reporters that he had "grave fears" for the missing and authorities were having difficulty identifying victims because of the condition of the bodies found.
The somber announcement came as authorities carried out more house-to-house searches in a desperate hunt for survivors.
The quake struck Tuesday, toppling buildings, buckling streets and ripping the facades of iconic churches, including the Christchurch Cathedral and the Cathedral of the Blessed Sacrament.
A series of aftershocks followed.
Officials said they had given up hope of rescuing at least 100 people who were trapped in the Canterbury TV building in downtown Christchurch. Police said they were "100% certain" no one in the building was still alive.
Authorities fear that trapped occupants in another structure, the Pyne Gould Corp. Building, are also dead.
Among those missing were 27 Japanese students, Japan's foreign ministry said. Most of them were students at language schools, and five were on personal study trips.
Kento Okuda, a Japanese student who was pulled from the rubble of the Toyoma Foreign Language College, told Japan's Asahi Shimbun newspaper that he was having lunch on the fourth-floor cafeteria when the floor gave way.
As he and others lay trapped under debris, the students shouted out to each other to get a count of how many of them were alive, Okuda told the newspaper.
Many of their fellow Japanese students did not respond.
But there have some rare rays of hope in the rescue efforts.
One was Anne Vos who was rescued Wednesday from the rubble of the Pyne Gould building in the central business district, according to Australian and New Zealand media.
Vos was able to call family members from her cell phone while covered by rubble.
"A couple of hours ago, I thought I'd had it," she told New Zealand network TV3 Tuesday. "I thought it was 'Goodbye Anne.' "
Like some 430 people who have been admitted to emergency rooms since the quake, Vos was taken to a hospital to recuperate.
Southern New Zealand has been hit by a series of quakes since September 4 when a 7.1-magnitude temblor struck the area. There were no deaths from that quake, which struck deeper below ground and farther away from Christchurch.
Tuesday's earthquake was part of the "aftershock sequence" from the September earthquake, the U.S. Geological Survey said.
CNN's Anna Coren contributed to this report.