Police arrested key student leaders of Hong Kong's pro-democracy protests as they cleared a protest camp in the volatile Mongkok district.

Joshua Wong and Lester Shum were among those arrested as hundreds of officers removed barricades and tents that had blocked key roads in the Chinese-controlled city for more than two months.

Although the protests have had no formal leadership structure, Wong and Shum were part of a group of students who many looked to as de facto leaders.

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Police officers arrest Joshua Wong, student leaderLam Yik Fei/Getty Images
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Joshua Wong and Lester Shum, student leaders, are pictured speaking to demonstrators on November 25Lam Yik Fei/Getty Images

Scuffles broke out when riot police moved against hundreds of protesters on Nathan Road.

There was no serious violence, and after about three hours the operation was complete and traffic was flowing through the area where demonstrators had camped out since late September.

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Police urge pro-democracy protesters to leave the main Nathan Road in Mongkok shopping districtBobby Yip/Reuters
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Police demolish a barricade set up by pro-democracy protesters on Nathan RoadBobby Yip/Reuters
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A police officer gestures as he stands on a barricade during the clearance of a major protest site in the Mongkok districtPhilippe Lopez/AFP
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A pro-democracy protester packs up before the police act on a court injunction to clear Nathan RoadLiau Chung-ren/Reuters
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A protester packs umbrellas and belongings ahead of an expected clearance by bailiffsPhilippe Lopez/AFP
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A pro-democracy protester walks away with his belongings after packing upAlex Ogle/AFP
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Police move a sofa as they clear away a pro-democracy protest camp on Nathan Road in the Mongkok district of Hong KongAlex Ogle/AFP
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Pro-democracy protesters clash with police on a street in Mongkok districtAnthony Kwan/Getty Images
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A bloodied police officer gestures during a clash with pro-democracy protesters on a street in Mongkok districtAnthony Kwan/Getty Images
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A police officer assists a colleague who was accidentally pepper-sprayed in Mongkok districtAnthony Kwan/Getty Images
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A worker uses heavy machinery to clear belongings left behind by pro-democracy protesters on Nathan RoadPhilippe Lopez/AFP
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Workers clean Nathan Road after police cleared a protest site which has occupied the street for weeksLiau Chung-ren/Reuters
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Traffic flows again along Nathan Road after it was reopenedChris McGrath/Getty Images

Mongkok has been a flashpoint for clashes between students and mobs intent on breaking up the protests, which have posed one of the biggest challenges to China's Communist Party leaders since the crushing of student-led pro-democracy demonstrations in Beijing in 1989.

The clearance of the Mongkok site is a big breakthrough in the authorities' efforts to end the most tenacious protest movement in Hong Kong's recent history, although it could trigger retaliatory protests elsewhere as activists regroup.

"After the clearance operation we don't have a leader," said protester Ken Lee, 19, who quit his job at a restaurant in October after the protests erupted. "We need to wait until tonight, it all depends on what happens tonight, if the majority of the people want to reoccupy the area or go to another location."

The two remaining protest zones are the sprawling main camp next to government headquarters on the edge of the financial district and a smaller one in the Causeway Bay shopping district.

The protesters are demanding that Hong Kong's government scrap a plan mandated by China's Communist leaders to use a panel of Beijing-friendly elites to screen candidates for the territory's top leader in inaugural 2017 elections.