Protesters defied an emergency decree and confronted police in Chile's capital Monday, continuing violent clashes, arson and looting that have left at least 11 dead and led the president to say the country is "at war." Police used tear gas and streams of water to break up a march by hundreds of students and union members on one of Santiago's main streets, but demonstrators who at first dispersed later regrouped elsewhere.

The unrest was triggered by a relatively minor increase in subway fares of less than 4% — but analysts have said the protests are fed by frustration from a long-building sense among many Chileans that they are not sharing in the nation's economic advances.

Police and soldiers guarded Chileans who formed long lines outside supermarkets before they reopened on Monday. Many of those stores had closed during a weekend in which dozens of stores were looted or burned.

Demonstrators light fires while clashing with riot police during a protest in Santiago, Chile Marcelo Hernandez via Getty Images

Only one of the city's six subway lines was operating because rioters had burned or damaged many of the stations. Officials said it could take weeks or months to fully restore service.

Get Breaking News Delivered to Your Inbox

Some two million students were forced to stay home from classes and many were unable to reach their jobs.

Conservative President Sebastián Piñera said Sunday night that the country is "at war with a powerful, relentless enemy that respects nothing or anyone and is willing to use violence and crime without any limits." He did not identify a specific enemy.

After receiving criticism for his comments, Piñera said he would meet with members of his administration and the opposition "to explore and hopefully advance toward a social agreement ... to a better solution for the problems that affect Chileans."

The government is also working on a reconstruction plan that would cover the hundreds of millions of dollars in infrastructure damaged during the protests, Piñera said.

His predecessor, Michelle Bachelet, issued a statement calling for dialogue and urging all sides to work "toward solutions that contribute to calming the situation."

Now the U.N. High Commissioner for Human Rights, Bachelet called for an investigation into all acts, by government or protesters, that have led to injuries and death.

Demonstrators clash with riot police during a protest. Protests began on Friday and developed into looting and arson, generating chaos in Santiago, Valparaiso and a dozen other cities resulting Marcelo Hernandez via Getty Images

The protests have shaken a nation noted for economic stability over the past decades, which has seen steadily declining poverty despite persistent high rates of inequality.

"I'm protesting for my daughter, for my wife, for my mother, not just for the 30 pesos of the Metro — for the low salaries, for the privileges of the political class, for their millionaire salaries," Andres Abregu, an Uber driver who complained he is still paying a student debt and cannot provide a decent life for his family, told the Associated Press.

Patricio Navia, a professor at the Center for Latin American and Caribbean Studies at New York University, told the Associated Press that protesters "feel the government cares more about the wealthy and that social programs help the very poor, but the rest of the population is left to care for themselves."

"They are not poor enough to get government subsidies nor rich enough to get government tax credits. They revolted to make their voice heard," he said.

Protesters march through the streets in Santiago, Chile Marcelo Hernandez via Getty Images

Otherwise peaceful Chilean protests are also often used as springboards for more violent action by smaller, hard-line factions that want to overturn the social system.

"As protests go, this can be interpreted as a hopeful one. People want it," Navia said. "There was destruction and looting, yes. But the majority of the people are in favor of peaceful protests. In fact, the riots are probably undermining the support for the protests."

Demonstrators defied a Monday curfew and gathered in the affluent Las Condes neighborhood outside the heavily guarded Military School in Santiago to bang pots, a traditional form of protest in South America.

The nation of 18 million people has won worldwide acclaim for its low poverty, inflation and unemployment, rarities in a region still struggling to leave behind economic dysfunction. But Chile's rate of inequality is among the worst in Latin America.

"You can argue that there's a middle class, that we decreased poverty, that today we don't have inflation, that the macro economy is in control, etcetera, etcetera," Marta Lagos, director of the polling firm Latinobarometro, told the Associated Press. "And all those arguments will be worthless to those people who don't make it to the end of the month."