VIENNA - Multiple rounds of shelling were heard at the Zaporizhzhia Nuclear Power Plant (ZNPP) on Monday amid the longest off-site power loss of the plant, posing "growing risks" to its nuclear safety and security, according to a UN nuclear watchdog statement.

The shelling occurred in the afternoon, totaling about 15 rounds at near and middle distance from the site. The ZNPP informed the International Atomic Energy Agency (IAEA) that two rounds of shelling struck around 1.25 km from the site perimeter, the IAEA statement said.

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No casualties have been reported and there was no immediate information of any damages. However, IAEA Director General Rafael Grossi said the shelling further underlined the constant dangers facing the ZNPP.

"The nuclear safety and security situation is clearly not improving. On the contrary, the risks are growing," Grossi said. "The plant has now been without off-site power for almost two weeks, forcing it to rely on emergency diesel generators for the electricity it needs to cool its shutdown reactors and spent fuel. This is an extraordinarily challenging situation."

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In the statement, Grossi called for "maximum military restraint near nuclear facilities" and said he will continue to engage with Russia and Ukraine to restore the plant's off-site power as soon as possible.

The ZNPP lost the connection to its last remaining 750 kilovolt line on Sept 23 during the conflict. Eight emergency diesel generators are currently operating to provide back-up electricity to the site.