It is unclear whether water from the huge reservoir at Ukraine’s Nova Kahovka dam that exploded last week can still be pumped into the nearby Zaporizhia nuclear power plant to cool the reactors, the UN nuclear watchdog said on Friday.

While the dam was the main source of water to cool the six reactors at Europe’s largest nuclear power plant, the plant can now receive water from other sources after the dam was blown, including a cooling pond reservoir that the International Atomic Energy Agency says it has enough water to last for months.

The dam blast has, however, further complicated an already difficult situation in ensuring the safe operation of Russian-held Zaporizhia, according to Reuters, citing the IAEA.

The bombing repeatedly knocked out external power lines that are also vital to ensuring the cooling needed to avoid nuclear meltdown.