Divers prepare themselves on a boat at the position of the sunk Hungarian riverboat as the search for the missing boat passengers continue on June 6, 2019 following a boat accident on the Danube river in Budapest. - The bodies of two more South Korean tourists have been found after a sightseeing vessel sunk in Budapest last week, bringing the death toll to 15, with 13 still missing, police said. The Mermaid with mainly South Koreans aboard overturned and sank May 29, seconds after colliding with a bigger cruise ship on a busy stretch of the Danube river in the heart of Budapest. (Photo by FERENC ISZA / AFP)

Divers prepare themselves on a boat at the position of the sunk Hungarian riverboat as the search for the missing boat passengers continue on June 6, 2019 following a boat accident on the Danube river in Budapest. - The bodies of two more South Korean tourists have been found after a sightseeing vessel sunk in Budapest last week, bringing the death toll to 15, with 13 still missing, police said. The Mermaid with mainly South Koreans aboard overturned and sank May 29, seconds after colliding with a bigger cruise ship on a busy stretch of the Danube river in the heart of Budapest. (Photo by FERENC ISZA / AFP)

Divers prepare themselves on a boat at the position of the sunk Hungarian riverboat as the search for the missing boat passengers continue on June 6, 2019 following a boat accident on the Danube river in Budapest. - The bodies of two more South Korean tourists have been found after a sightseeing vessel sunk in Budapest last week, bringing the death toll to 15, with 13 still missing, police said. The Mermaid with mainly South Koreans aboard overturned and sank May 29, seconds after colliding with a bigger cruise ship on a busy stretch of the Danube river in the heart of Budapest. (Photo by FERENC ISZA / AFP)

Divers prepare themselves on a boat at the position of the sunk Hungarian riverboat as the search for the missing boat passengers continue on June 6, 2019 following a boat accident on the Danube river in Budapest. - The bodies of two more South Korean tourists have been found after a sightseeing vessel sunk in Budapest last week, bringing the death toll to 15, with 13 still missing, police said. The Mermaid with mainly South Koreans aboard overturned and sank May 29, seconds after colliding with a bigger cruise ship on a busy stretch of the Danube river in the heart of Budapest. (Photo by FERENC ISZA / AFP)

Experts and rescue team members stand on a boat at the position of the sunk Hungarian riverboat as the search for the missing boat passengers continue on June 6, 2019 following a boat accident on the Danube river in Budapest. - The bodies of two more South Korean tourists have been found after a sightseeing vessel sunk in Budapest last week, bringing the death toll to 15, with 13 still missing, police said. The Mermaid with mainly South Koreans aboard overturned and sank May 29, seconds after colliding with a bigger cruise ship on a busy stretch of the Danube river in the heart of Budapest. (Photo by ATTILA KISBENEDEK / AFP)

Experts and rescue team members stand on a boat at the position of the sunk Hungarian riverboat as the search for the missing boat passengers continue on June 6, 2019 following a boat accident on the Danube river in Budapest. - The bodies of two more South Korean tourists have been found after a sightseeing vessel sunk in Budapest last week, bringing the death toll to 15, with 13 still missing, police said. The Mermaid with mainly South Koreans aboard overturned and sank May 29, seconds after colliding with a bigger cruise ship on a busy stretch of the Danube river in the heart of Budapest. (Photo by ATTILA KISBENEDEK / AFP)

Experts, rescue team members and a Hungarian diver stand on a boat at the position of the sunk Hungarian riverboat as the search for the missing boat passengers continue on June 6, 2019 following a boat accident on the Danube river in Budapest. - The bodies of two more South Korean tourists have been found after a sightseeing vessel sunk in Budapest last week, bringing the death toll to 15, with 13 still missing, police said. The Mermaid with mainly South Koreans aboard overturned and sank May 29, seconds after colliding with a bigger cruise ship on a busy stretch of the Danube river in the heart of Budapest. (Photo by ATTILA KISBENEDEK / AFP)