BEIRUT (Reuters) - An upsurge of violence in Lebanon’s protests against the ruling elite, with police meting out beatings and protesters hurling stones, has alarmed rights groups and whipped up public fury.

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After a brief lull in largely peaceful protests since October, people filled the streets again this week, angry at a political class that has steered Lebanon into its worst economic crisis since a 1975-1990 civil war.

On Tuesday and Wednesday, police wielding batons and firing tear gas wounded and arrested dozens as protesters lit fires and smashed bank facades and ATMs, Reuters journalists saw.

“These past two nights, they (police) were really barbaric,” said Cynthia Sleiman, a charity worker and protester who ended up in hospital after Wednesday night’s violence in Beirut.

“I had just arrived and was looking for my friends when the policeman grabbed me, hitting me on the head and neck. I fell to the ground and blood was streaming out,” she said.

Lebanon’s Internal Security Forces (ISF) said they were pursuing rioters and 100 policemen were injured this week. “The force member is suffering daily in the street,” ISF chief Imad Othman said on Thursday. “He is not a robot, he is a human.”

A security source said at least 80 protesters were injured in two days and 72 others arrested. Many of those in detention would be released on Thursday, the source said.

Since the protests led Prime Minister Saad al-Hariri to resign in October, politicians have failed to agree a new cabinet or rescue plan for the heavily-indebted economy. The Lebanese pound has lost nearly half its value, dollar shortages have driven up prices and confidence in banks has collapsed.

Azza al-Masri, a media researcher also injured on Wednesday, said she saw a woman faint after police beat her up. “The viciousness was unlike anything I’ve seen,” she said.

Activists believe police violence may indicate Lebanon’s establishment has lost patience with protesters and is also stung by public wrath against banks, which have curbed access to savings and blocked most transfers abroad.

Human Rights Watch’s Beirut director Lama Fakih told Reuters the group was concerned at excessive force by security forces amid rising frustrations on both sides. She said there was no “strong message” from government that police would be held responsible.

A Lebanese media group said 15 journalists were attacked on Wednesday. One of them was a Reuters video journalist, who was treated in hospital for head injuries and released.

On Thursday, lawyers, journalists and activists gathered at the interior ministry and the justice palace in Beirut to complain about police violence. Interior Minister Raya al-Hassan told reporters she had not ordered a clampdown and denounced attacks on media, while also urging understanding for police.