MOSCOW - Russian truckers indignant at a new tax have caused huge tailbacks across the country, as they block roads in a rare mass protest rattling the authorities under President Vladimir Putin.
Long lines of lorries halted traffic on highways in some 20 regions to demonstrate against the levies introduced on November 15 - and the son of a close Putin ally responsible for collecting them.
"They have to live and feed their children," Igor Pasynkov, the head the country's long-distance truckers association, said of the drivers involved in the demonstrations. "That's why they are protesting." In the volatile North Caucasian republic of Dagestan, more than 1,000 truck drivers reportedly took part in the protest movement.
Trucks were parked up for tens of kilometres on the road heading to Azerbaijan, independent newspaper Novaya Gazeta reported.
Dagestan's disgruntled truck drivers have threatened to block the roads leading to Moscow on November 30 if the tax is not annulled, a call that had been echoed in other regions.
But while the protest has caused major disruptions across the country it has received little coverage in Russia's tightly controlled state media and has only just begun garnering official attention.
"We called TV stations. They refused to come and the police were called on us," a truck driver who identified himself as Dibir told Novaya Gazeta.
That may be explained by the target of many of the protesters' ire - the son of billionaire Arkady Rotenberg, a long-time friend and judo partner of Putin.
Rotenberg junior, Igor, part owns the company that scooped the lucrative contract to collect the transportation tax.
For critics it is yet another example of the crony capitalism rife among Putin's elite that has seen those close to the ex-KGB agent leader amass vast fortunes, even as the country has slumped into economic crisis.
The Russian government - coping with economic woes linked to low oil prices and Western sanctions - said it hoped to collect more than 40 billion rubles (570 million euros, $600 million) with the new tax in 2016.
Authorities say the new tax is needed to help compensate for the damage heavy goods vehicles inflict on the country's roads, but truck driver association head Pasynkov slammed it as "not adapted to reality".
"The truckers' protest movement is both economic and social, a very dangerous combination for political stability," said political scientist Yekaterina Schulmann of the Russian Academy of National Economy and Public Administration.
"I think authorities will make concessions. The risks are too high," she added.
In a sign that the demonstration is beginning to rattle the authorities, the Kremlin's business ombudsman Boris Titov raised the truckers' issues in a letter to Putin.
Titov warned that the tax - and the discontent it has sparked - could cause costly food supply disruptions across the country.
And after having remained silent on the issue, the government transportation agency has agreed to create a working group to address the matter.
Deputy Prime Minister Arkady Dvorkovich on Wednesday announced that the 40,000-ruble fine for trucks not equipped with metering devices would be lowered.
Such protest movements are rare in Russia as the authorities have clamped down on demonstrations after smothering a wave of anti-government protests that greeted Putin's return for a third term as president in 2012.
A survey by the independent Levada Centre last December found that an overwhelming 83 percent of Russians would be reluctant to take part in any political protest.
Putin enjoys a vertiginous approval rating - helped by the strictly controlled state media - in spite of economic troubles that have seriously shrunk Russians' purchasing power.
But analysts warn that public adulation could prove brittle and spill over into broader discontent.
"If the situation does not cool off, the economic crisis will become a social crisis," said Konstantin Kalachev, the head of a Moscow-based political think tank.
"I think authorities cannot let roads to Moscow be blocked and that a solution will be found," he said.
In Saint Petersburg, where several dozen lorries slowed traffic last week, the leader of a local truckers' organisation insisted drivers would not back down until the tax was scrapped.
"In Dagestan, truck drivers are already calling for Putin to step down," said protest movement member Alexander Rastorguev. "If authorities don't react, the drivers here will ask for the same."