Chile's Government has extended a state of emergency to cities in its north and south, as the death toll from violent clashes and arson attacks rises to at least seven.

Key points: Riots erupted in the capital Santiago after an increase in public transport costs

Riots erupted in the capital Santiago after an increase in public transport costs More than 1,400 people were charged on Sunday in connection with that day's protests

More than 1,400 people were charged on Sunday in connection with that day's protests The situation has drawn comparisons with the dictatorship of General Augusto Pinochet

The decision to extend the emergency measure came amid an "escalation of violence and vandals," said Interior Minister Andres Chadwick.

Mr Chadwick cited 70 "serious incidents of violence" yesterday including the looting of 40 supermarkets and other businesses, with at least seven people dead.

Protests led by students began two weeks ago as Santiago and other Chilean cities were engulfed by several days of riots, after the increase in public transport costs.

Week-long protests over a subway fare hike in Chile turned violent, with arson attacks across the capital. ( AP: Esteban Felix )

"We are at war against a powerful enemy, who is willing to use violence without any limits," President Sebastian Pinera said.

Mr Pinera confirmed the state of emergency he declared for Santiago, which brought the military onto the streets, would be extended to the north and south of the capital.

"Today is not the time for ambiguities. I call on all my compatriots to unite in this battle against violence and delinquency," he said.

The violence prompted Mr Pinera to suspend a subway fare hike and declare a state of emergency which would be rolled out to Antofagasta, Valparaiso, Valdivia, Chillan, Talca, Temuco and Punta Arenas.

Boots on street recalls memories of Pinochet dictatorship

Military vehicles patrolled the streets for the first time since the Pinochet dictatorship ended in 1990. ( AP: Esteban Felix )

Mr Pinera said Santiago's metro and bus system would operate a partial service, along with hospitals and some schools and creches, and appealed for Chileans to band together and help their neighbours to get on with their lives and remain safe.

"We are very aware that [the perpetrators of riots] have a degree of organisation, logistics, typical of a criminal organisation," he said.

Mr Chadwick said military and police numbers were at 10,500 in Santiago and would be reinforced where necessary.

There was transport gridlock in Santiago and chaos at the international airport on Sunday, with flights into and out of the capital suspended or cancelled because crew members and airport staff were unable to get to work, the city's governor said.

Protests led by students began two weeks ago over fare hikes on public transport. ( AP )

Prosecutors said 1,462 people had been charged by mid-afternoon on Sunday in connection with that day's protests.

Of these, 614 were charged in Santiago, and that followed 179 arrests in the city on Saturday.

The military authorities mandated by Mr Pinera with re-establishing order in Santiago declared another night-time curfew in the capital as the Government struggled to contain violent protests, looting and arson.

The General in charge of security in Santiago announced the curfew would begin at 7:00pm (local time) on Sunday and end at 6:00am on Monday, with soldiers and tanks patrolling the streets for the first time since the military dictatorship of General Augusto Pinochet ended in 1990.

However, several large demonstrations continued past the mandated curfew hour, according to local media reports.

Reuters