Police guard the scene where a man pointed a gun at Argentina's Vice President Cristina Fernandez [AP Photo]

A man was detained Thursday night after he aimed a handgun at point-blank range toward Argentina's politically powerful Vice President Cristina Fernandez, and President Alberto Fernandez said the assassination attempt failed because the gun did not fire.

"A man pointed a firearm at her head and pulled the trigger," the president said in a national broadcast.

He called it "the most serious incident since we recovered democracy" in 1983 and urged political leaders, and society at large, to repudiate the incident.

Supporters of the vice president have been gathering in the streets surrounding her home since last week, when a prosecutor called for a 12-year sentence for Fernandez as well as a life-long prohibition in holding public office as part of a case involving alleged corruption in public works during her 2007-2015 presidency. Fernandez, who is not related to the current president, has denied all charges.

The president spoke shortly after video from the scene broadcast on local television channels showed Fernandez exiting her vehicle surrounded by supporters outside her home when a man could be seen extending his hand with what looked like a pistol.

The vice president ducked as supporters surrounding the person appeared shocked at what was happening amid the commotion in the Recoleta neighborhood of Argentina's capital.

The man, whose identity was not released by authorities, was detained seconds into the incident.

The president said the firearm had five bullets "and didn't fire even though the trigger was pulled."

There was no indication that the vice president suffered any harm. Her wheareabouts were unknown.

"A person who was identified by those who were close to him who had a gun was detained by (the vice president's) security personnel," Security Minister Anibal Fernandez told local cable news channel C5N.

The minister said he wanted to be careful in providing details until the investigation learned more.

Unverified video posted on social media shows the pistol almost touched Fernandez's face.

State-run news agency Telam identified the alleged gunman as Fernando Andres Zabak, a Brazilian citizen. Officials had not confirmed the information.

Government officials were quick to describe the incident as an assassination attempt.

"When hate and violence are imposed over the debate of ideas, societies are destroyed and generate situations like the one seen today: an assassination attempt," Economy Minister Sergio Massa said.

Ministers in President Alberto Fernandez's government issued a news release saying they "energetically condemn the attempted homicide" of the vice president. "What happened tonight is of extreme gravity and threatens democracy, institutions and the rule of law," reads the release.

Former President Mauricio Macri also repudiated the attack. "This very serious event demands an immediate and profound clarification by the judiciary and security forces," Macri wrote on Twitter.

Patricia Bullrich, president of the opposition Republican Proposal party, criticized the president, saying he is "playing with fire" because "instead of seriously investigating a serious incident, he accuses the opposition and the press, decreeing a national holiday to mobilize activists."

Tensions have been running high in the upper class Recoleta neighborhood since the weekend, when the vice president's supporters clashed with police in the streets surrounding her apartment amid an effort by law enforcement officers to clear the area. Following the clashes what had been a strong police presence around the vice president's apartment was reduced.

When Fernandez leaves her apartment every day at around noon, she greets supporters and signs autographs before getting in her vehicle to go to the Senate. She repeats the same routine every evening.

Following the incident, allies of the vice president quickly pointed the finger at the opposition for what they say is hateful speech that promotes violence. In recent days, several key officials have said opposition leaders were looking for a fatality.

"This is a historic event in Argentina that must be a before-and-after," Buenos Aires Gov. Axel Kicillof said.

Regional leaders also condemned the attack.

"We send our solidarity to the vice president in this attempt against her life," Venezuela's President Nicolas Maduro said on Twitter.

Former Brazilian President Luiz Inacio Lula Da Silva, who is a candidate in that nation's presidential election next month, also expressed solidarity with Fernandez, calling her a "victim of a fascist criminal who doesn't know how to respect differences and diversity."