(Adds Maduro quotes, response by Panama)
By Andrew Cawthorne and Eyanir Chinea
CARACAS, Feb 20 (Reuters) - Venezuelan security forces and demonstrators faced off in streets blocked by burning barricades in several cities on Thursday in an escalation of protests against President Nicolas Maduro's socialist government, witnesses said.
At least five people have died since the unrest turned violent last week, with scores of injuries and arrests.
The demonstrators, mainly students, blame the government for violent crime, high inflation, product shortages and alleged repression of opponents.
In affluent east Caracas overnight, security forces fired teargas and bullets, chasing youths who threw Molotov cocktails and blocked streets with burning trash, witnesses said.
Residents in middle-class neighborhoods banged pots and pans at windows in a traditional form of protest, and demonstrators were out again from early on Thursday.
"I declare myself in civil disobedience," read one banner held up by demonstrators spread across a Caracas road.
There were similar scenes in the western Andean states of Tachira and Merida that have been especially volatile since hardline opposition leaders called supporters onto the streets in early February demanding Maduro's departure.
In San Cristobal city, which some residents are describing as a "war zone", many businesses remained shut as students and police faced off in the streets again on Thursday.
Maduro said "special measures" would be taken to restore order in Tachira. "We won't let them turn it into a Benghazi," he said, referring to the violence-wracked Libyan city.
Tensions have escalated since opposition leader Leopoldo Lopez, a 42-year-old Harvard-educated economist, turned himself in to troops this week. He is being held in Caracas' Ramo Verde jail and faces charges of fomenting the violence.
"Change depends on every one of us. Don't give up!" Lopez's wife Lilian Tintori said via Twitter on Thursday.
Local TV channels are providing almost no live coverage of the unrest, so Venezuelans are turning to social media to swap information and images, though falsified photos are circulating.
Both sides rolled out competing evidence of the latest violence on Thursday, with ruling Socialist Party governors showing photos and video of charred streets and torched vehicles, while the opposition posted footage of brutal behavior which they said was by national guard troops.
Caracas was calmer by lunchtime on Thursday.
There was a little less traffic than normal, and most people appeared to have returned to work. But the events of the night were on everyone's lips.
Panama's President Ricardo Martinelli said via his Twitter account on Thursday that the country was calling in its ambassador for consultations, adding "We deplore the violent situation that our brother country is going through."
Maduro, narrowly elected last year to succeed socialist leader Hugo Chavez after his death from cancer, says Lopez and others are in league with the U.S. government and want a coup.
The latest direct victim of the unrest was a college student and local beauty queen, Genesis Carmona, 22, shot in the head during a demonstration in the central city of Valencia.
In an indirectly linked death, state television channel VTV said the mother of a well-known young presenter died as she was being rushed to hospital on Wednesday in Caracas.
VTV said she was suffering from high blood pressure brought on by a rowdy protest outside her home. It said she then suffered a heart attack while the ambulance carrying her was stuck in gridlock due to opposition supporters blocking roads.
Maduro says "fascist groups" are trying to create a crisis to topple his administration.
"There is an international campaign to justify a foreign intervention in Venezuela," he said in a combative, nationally televised address late on Wednesday.
Speaking in Mexico, U.S. President Barack Obama criticized Maduro's government for arresting protesters and urged it to focus on addressing the "legitimate grievances" of its people.
Street protests were the backdrop to a short-lived coup against Chavez in 2002 before military loyalists and supporters helped bring him back.
There is no evidence the military, which was the decisive factor in 2002, may turn on Maduro now.
Detractors call Lopez a dangerous hothead. He has frequently squabbled with fellow opposition leaders and was involved in the 2002 coup, even helping arrest a minister.
Though the majority of demonstrators have been peaceful, an increasingly prominent radical fringe has been attacking police, blocking roads and vandalizing buildings.
Rights groups say the police response has been excessive, and some detainees say they were tortured. (Additional reporting by Daniel Wallis and Girish Gupta; Editing by Brian Ellsworth and James Dalgleish)