Sveta has no doubt about why the Ukrainian-held southern city of Mykolaiv, a ship-building centre that is home to a half a million people, has gone without fresh water for the past six months.

"They (the Russians) are committing genocide against us," she growled as she waited this week with dozens of others to fill containers with water from tanks hauled to a downtown thoroughfare aboard an electric tramway repair car.

The shutoff is bitter affirmation for Sveta, and some 220,000 other residents who remain in the oft-shelled city, that Russian President Vladimir Putin's war on Ukraine extends beyond the battlefield to civilian infrastructure.

The Kremlin dramatically intensified strikes on energy facilities with pre-winter missile and drone onslaughts over the past two weeks, in what Putin has called legitimate retaliation for an attack on Russia's bridge to Crimea.

The attacks have disrupted electricity across large parts of Ukraine, killing dozens of people and leaving other places without access to clean water.

But Mykolaiv's water problems have gone on much longer.

The Russians, Ukrainian officials say, closed the city's freshwater intakes in the adjacent Kherson province after they overran the region as part of what Putin calls "a special military operation."

"We don't know whether this was an intentional explosion or an accidental ammunition strike," municipal water chief Borys Dydenko told Reuters. He said he believed the Russians shut the intakes to avenge Ukraine's closure of freshwater supplies to Crimea in 2014. The Kremlin and the Russian defence ministry did not immediately respond to requests for comment.