SMH.au | Jun. 15, 2012

A ROW has erupted in Moscow after a member of parliament accused the Kremlin of using chemicals to induce the torrential downpours that soaked protesters at an anti-Putin demonstration this week.

Rain drenched tens of thousands of people as they gathered for the biggest opposition event since Vladimir Putin's inauguration as President last month. A thunderstorm in the afternoon caused protesters to disperse more than an hour before the rally's end.

The weather may have been manipulated by the authorities, opposition leader and Duma deputy Ilya Ponomaryov wrote on his blog. ''An anomalously high content of silver iodide'' was found in rainwater collected during the day and analysed by chemists, he said.

Experts countered there was little evidence to suggest authorities could induce rain at specific places and times.

Thundery showers were forecast well in advance, pointed out the deputy director of Russia's Hydrometeorological Centre, Dmitry Kityov. While he said it was theoretically possible to artificially induce rainfall, ''this sort of thing has never been seen before''.

Officials dismissed the charges and said they had actually been seeking to prevent rainfall on Tuesday, which was also Russia Day, a national holiday.

Eight military aircraft had been deployed to scatter 1.5 tonnes of reagent to guarantee good weather, Lieutenant-Colonel Vladimir Deryabin said.

There had been wry jokes among protesters that the Kremlin was behind the inclement weather.

''It looks like yesterday's joke about Putin and the rain has turned out to not entirely be a joke,'' wrote Mr Ponomaryov, who said he was seeking to prove his suspicions.