Authorities rushed police reinforcements to towns where hundreds of youths took to the streets, a newspaper reported, as neighbouring Tunisia was also struck by more protests in a wave of similar unrest.
Youths blocked major regional roads around Boumerdes, about 60 kilometres (35 miles) east of Algiers, and Bejaia, 200 kilometres further east, the online edition of the El-Watan newspaper reported.
Authorities sent in "a large number of convoys of anti-riot police," it said.
Shops in the capital meanwhile shut up early after rioting late Wednesday in which dozens of youths hurled stones at a police station in the Bab el Oued area, set alight several shops and barricaded roads with flaming tyres.
"They hurled stones at the anti-riot police in the area," a resident told AFP by telephone.
A dealership for Renault, a carmaker from former colonial ruler France, was attacked and torched, about a dozens of its vehicles destroyed, an AFP photographer said.
A top-end shoe shop even cleared its shelves ahead of nightfall Thursday. "We are closing to wait and see what will happen," an employee said.
Also Wednesday a similar demonstration was held in Oran, 430 kilometres west of the capital, where protesters burned tyres, blocked roads with tree trunks and hurled objects at drivers, the Oran Daily reported.
Youths forced open a warehouse to steal sacks of flour, it said, with the cost of flour among those that have risen in recent days.
Demonstrators blocked roads on Monday in Tipaza, west of the capital, in protest against food prices and difficult living conditions.
There have been similar protests, some turning violent and resulting in injuries, across the country for months, focussed on costs, employment, lack of social housing and allegations of corruption.
The General Union of Algerian Traders and Artisans said prices had risen between 20 and 30 percent in recent days, with the costs of sugar and oil up sharply since the start of the month.
In an attempt to calm the rising anger, Commerce Minister Mustapha Benbada said Wednesday the food price rises were not unique to Algeria but part of a worldwide trend.
"The state will continue to subsidise essential items," he said.
About 75 percent of Algerians are under the age of 30, and 20 percent of the youth are unemployed, according to the International Monetary Fund.
President Abdelaziz Bouteflika pledged in 2009 to build a million apartments not replaced since a 2003 earthquake, while growth of the population -- which has tripled to 35.6 million since independence from France in 1962 -- has added to strains on the availability of housing.
"I fear that the situation will explode," Research Centre of Applied Economy for Development sociologist Mohammed Saib Musette told AFP.
"There is a contagion effect, mainly when we think about what has happened with Tunisia," he said.
A wave of demonstrations against unemployment and the cost of living erupted in Tunisia on December 17 after a university student set himself alight in a protest. He died of his wounds on Tuesday.
Thousands of Tunisian lawyers joined protests on Thursday with more rallies and even an attempted suicides after weeks of disturbances that have rattled the government.
The two north African countries, along with Morocco, are in a similar situation in that they have been unable to accommodate their young graduates and suffered in the global economic crisis, analysts said.
"In these three countries, there have been efforts in the area of education but they did not think of ways to integrate young graduates into the community, an integration that happens through employment," said economist Driss Benali from Rabat's Mohammed V University.