Japanese officials said they failed on Sunday in repeated attempts to seal a crack they had identified as one source of radioactive water leak into the Pacific.

Workers at the crippled Fukushima Daiichi nuclear plant nuclear are struggling to stop the leaks but the government says doing so may take months as several issues—such as flooding and power outages—have taken far longer to solve than originally projected.

The Nuclear Safety Agency said: “It will be a few months before it’s under control. We’ll face a crucial turning point then.”

"Efforts to block the leakage of radiative water, isolate it, seal nuclear reactors and cool them may take weeks or even months," Hidehiko Nishiyama, deputy director-general of the Nuclear and Industrial Safety Agency told a news conference on Sunday.

Chief cabinet secretary, Yukio Edano, says medical teams are monitoring the health of children living close to the plant.

"There is a higher possibility that radiation levels will affect children more," he said.

"Therefore, we have conducted three times examinations of possible effects on children's thyroids."

On Saturday, plant operators identified an 8-inch crack in the concrete pit in one of its reactors that may be leaking radioactive water into the ocean.

When efforts to seal the crack with concrete were unsuccessful Saturday, crews tried a mixture of sawdust, newspapers and a chemical similar to one used in diapers to absorb liquid to plug the leak, but that too fell short.

Meanwhile, the operator of the stricken nuclear plant said that two of its engineers who went missing since the day the earthquake and tsunami hit Japan last month had been confirmed dead. TEPCO saud a 21-year-old and a 24-year-old were killed when the tsunami hit after an earthquake three weeks ago.