(Updates with details of accidents, protests)
PARIS, Nov 17 (Reuters) - A motorist accidentally hit and killed a protester taking part in a campaign of road blockades across France on Saturday, as thousands gathered on motorways in a backlash against higher fuel taxes.
The demonstrators, part of a grassroots movement dubbed the "yellow vests", caused logjams on highways and blocked roundabouts as they railed against the fuel tax hikes introduced by President Emmanuel Macron.
The protests, largely orchestrated on social media and which aimed to prevent road access to some fuel depots and airports, have also drawn broader support from some voters dissatisfied with Macron's economic reforms and his governing style.
At a blockade on a road in the southeastern department of Savoie, a driver panicked when protesters surrounded her car and she accelerated, hitting and killing a woman demonstrator, French Interior Minister Christophe Castaner said in televised comments.
Sixteen people were lightly injured in other accidents across the country, and a person run over by a car in northern France was in a critical state, according to the interior ministry, which estimated some 50,000 demonstrators were participating in Saturday's protests.
Some incidents occurred as drivers not taking part tried to get around the blockades, police sources said.
Protesters gathered at sensitive flashpoints including the entry to a tunnel under the Mont-Blanc mountain in the Alps, and traffic was backed up on several highways.
Demonstrators were also on the march in cities, including Marseille where around 100 people, wearing the high visibility vests drivers keep in their cars, blocked roads around its port.
The backlash is the latest confrontation between Macron and voters, mostly based in the countryside and provincial towns and cities, who view the former investment banker as the representative of a remote urban elite.
During his 18 months in power, Macron, 40, has often pushed through reforms, including an overhaul of indebted state rail operator SNCF, in the face of opposition from labour unions.
But the "yellow vest" movement has snowballed swiftly over the past month, catching Macron and even opposition parties off guard. It has already prompted a rare concession from the government, which announced last Wednesday fresh funds to help motorists on the lowest incomes.
The higher fuel taxes were approved in late 2017 but started to bite as oil prices surged in October, even though they have since eased off somewhat.
The diesel tax increases are designed to encourage drivers to switch to more environmentally-friendly cars. (Reporting by Sarah White, Caroline Pailliez, Pierre Savary and Jean-Francois Rosnoblet Editing by Gareth Jones)
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