London - Police arrested nearly 300 people as thousands of Extinction Rebellion climate activists blocked main roads and at least two bridges in central London on Monday's opening day of global protests by the group.
The Metropolitan Police reported a total of 280 arrests across London by late in the evening. Officers had to drag away protesters who were sat in the middle of a main road into Parliament Square.
Other protesters erected scaffolding, tents, vehicles and makeshift buildings to block roads, under the close watch of hundreds of uniformed police.
The police thwarted plans by religious activists to create a "faith bridge" blockade along Lambeth Bridge, which was sealed off by police but blocked by protesters at one end.
One elderly protester who travelled from the nearby city of Oxford said he was escorted off the bridge by dozens of police, adding that another man was arrested for obstruction.
"But they were already suffering [in Malawi] 25 years ago when they couldn't explain why they're getting droughts year after year," Simon said. "Things haven't improved... And so I'm carrying a cross because this cross is a symbol of hope."
Caroline Lucas, Britain's sole Green Party member of parliament, said the protests are "sending a clear message to government to say we need to tell the truth about the climate emergency."
"We need radical action now," Lucas said in a video message from one of the protests.
"There is more political leadership on the streets than I've ever seen in the House of Commons," she said, referring to parliament's elected house, where she sits.
There's more political leadership being shown by @ExtinctionR on London's streets than I've ever seen in the House of Commons
Extinction Rebellion UK said at least 23 people were arrested as police tried to remove a model of a Trident nuclear-capable missile that was erected in a "peace blockade" outside Britain's Defence Ministry earlier Monday.
The group has promised "the largest regenerative movement of civil disobedience in history."
The police said 11 people were arrested over the weekend.
Extinction Rebellion, or XR, said the police also seized six vehicles, plus tents, toilets and "disabled access equipment" from a London warehouse.
"They really know how to get to people," Steven said. "They can't protest with a full bladder. Well done, police!"
Smaller Extinction Rebellion protests were held in cities across the globe on Monday, including Berlin, Paris, New York and Wellington.