There are a lot of things you can use to make a street barricade.
Anti-government protesters in Venezuela are not short of imagination when it comes to blocking streets in cities across the country, even as the President calls for dialogue.
"It is not just students who are protesting against the government of President (Nicolas) Maduro," Noemy Becerra, a resident of the city of Valencia, told CNN's iReport, referring to what had begun weeks ago as a youth movement. "These are neighbors in protest, with burning objects, debris and pot-banging included."
Maduro has called for a peace conference on Wednesday, inviting mayors, governors and leading lawmakers to sign a deal renouncing violence.
The outcome of those talks was uncertain, as protesters blame the government itself for the violence that has claimed 13 lives.
The barricades -- on streets of major cities such as Caracas, Valencia, Maracaibo and San Cristobal -- are not just a form of protest, but an attempt to protect residents from what they say is an abusive National Guard force.
In Valencia on Monday, a young woman suffered a brutal attack where she appeared to be struck repeatedly by a female member of the National Guard using her helmet.
The hard-to-watch scene, which has gone viral on social media, was captured by a photographer from the local newspaper, the Carabobeño.
One photo shows the servicewoman straddling a female protester on the ground at chest level while unhooking her helmet. The next shot shows what appears to be the military woman delivering a glancing blow to the protester.
CNN could not independently confirm the incident, but a video posted on YouTube appeared to show the same scene, where the blows allegedly being levied by the servicewoman can be seen.
CNN reached out to state authorities to comment about the incident, but had not received a response.
The blowback on social media was intense -- people claimed they identified the servicewoman, and posted her name, Facebook profile and even address on the Internet.
The barricades are slowing life in the streets.
"Valencia is completely paralyzed!" resident Carmen Teresa Peña told CNN iReport. "We need to be heard, and there is no Venezuelan media that will broadcast what is happening."
In the capital, barricades also became focal points of the protests.
With tensions running high, some turned to humor, even at the blockades.
One sign posted at a Caracas barricade was made to look like a men-at-work sign: "Stop! Stop! Excuse the mess. We are working for Venezuela."
March in the capital
The largest protest on Tuesday was a student-led march to the Cuban Embassy. The Venezuelan opposition accuses the communist Cuban government of interfering in Venezuelan affairs and infiltrating their military.
The Cuban Embassy in Caracas was the site of a protest march in 2002, when the late President Hugo Chavez was briefly ousted from office. That protest -- where opposition figures entered embassy grounds -- remains one of the most controversial from that tense time.
Washington expels diplomats
Also Tuesday, the United States announced it is expelling three Venezuelan diplomats in a tit-for-tat following the expulsion of three U.S. diplomats from that country, the State Department said.
Venezuela expelled the U.S. officials earlier this month in connection with accusations that the United States is behind the protests in Venezuela in an attempt to destabilize the government. The United States has denied the allegations.
Venezuelan Embassy First Secretary Ignacio Luis Cajal Avalos, First Secretary Victor Manuel Pisani Azpurua and Second Secretary Marcos Jose Garcia Figueredo were declared personae non gratae.
They have 24 hours to leave the United States.
As tensions inside Venezuela intensify, Sen. Bob Menendez, D-New Jersey, told CNN Tuesday that the United States should weigh stepping up efforts to condemn the violence by revoking visas or freezing bank accounts.
The imprisonment of opposition leader Leopoldo Lopez, Menendez said, "is one example that, in fact, we should be considering targeted sanctions against those in the Maduro government who are using violence. ... Those are strong messages that are not interventionist, but are about human rights and democracy."
CNN's Ione Molinares, Juan Carlos Lopez and Catherine E. Shoichet contributed to this report.