(This March 31 story, corrects paragraph 7 to say Cani dived to 180 metres, not 200 metres, adds Starnawski dive to 265 metres)
Czech divers are preparing to search the world's deepest underwater cave again to see if there is more to be discovered from its already record-breaking depths.
Last September researchers identified the flooded limestone cave, called Hranicka Propast and located 300km (186 miles) east of Prague, as the deepest of its kind when they reached 404 metres below Earth's surface.
Access to the underwater part of the cave is inside a gorge nestled within a forest.
Exploration was halted then because the cord of a submersible robot used for the expedition was not enough to reach the bottom of the cave, Michal Guba from the Czech Speleological Society said.
The mini-submarine then got tangled in its cords on its way up and it has remained in the water, diver David Cani said, adding it could be hopefully retrieved in April.
The cave, which has become tourist attraction, is not accessible during winter.
Cani went as deep as 180 metres, while fellow diver Krzysztof Starnawski reached a depth of 265 metres in a separate dive, according to Gupa, leaving the rest of the journey to a robot.
"It is dark, gloomy there, but I had a euphoric feeling when I got there," Cani said, referring to the complete darkness of the underwater cave.
"The rock (of the cave) goes 1.2 kilometres deep, (but) if we reach 500 metres, we will be happy too."
Until now, Italy's Pozzo del Merro was considered the world's deepest flooded cave at 392 metres.
(Reporting by Jiri Skacel; Writing by Robert Muller; Editing by Vin Shahrestani)