Chile's president has appealed for calm in the earthquake-ravaged city of Concepcion, vowing¹ a stern response to any renewal² of looting and violence.

智利总统呼吁康赛普西翁城的受灾群众保持镇静，并郑重宣告将对任何抢劫、暴力行动采取严厉措施。

Troops are posted on street corners in the middle of Concepcion

Michelle Bachelet says 14,000 troops are now in the region, after dozens of people were arrested on Monday.

A BBC reporter in Concepcion says police are now posted on street corners in the city centre, but says that aid convoys³（护航，护送） are yet to reach the needy⁴（有需要的人，困难职工） .

The death toll⁵（死亡人数） from the 8.8-magnitude quake now stands at 795, officials say.

Emergency workers also say 19 people are still unaccounted for（下落不明的） .

'Necessary measure'

A special air route is being set up to deliver aid from the capital, Santiago, to Concepcion, 430km (270 miles) away.

But security in the city remains⁶ a key concern after shops and homes were looted（抢劫，洗劫） on Monday and police made large numbers of arrests.

The deteriorating⁷（退化，恶化） security situation in Concepcion comes despite the influx⁸（流入，汇集） of thousands of troops to reinforce local police.

"We can say that, according what we've been told from the area, the situation in Concepcion is under control today," President Michelle Bachelet said on Tuesday.

But, she added, authorities would take any "necessary measure" to stop renewed looting.

"Our principle objective is to go and help people tackle the emergency in the disaster zone.

"I want them [looters] to understand this and that they'll receive rigorous（严格的，严酷的） legal action. We will not tolerate such actions."

Many of the city's 500,000 inhabitants are short of food and have seen their water and electricity supplies cut off.

Aid agencies have yet to reach Concepcion, reports the BBC's Andy Gallacher, who has reached the city, and many people are still awaiting water, food and mattresses⁹.

However, at least two police officers appear to be posted on every corner in the city centre, our correspondent says.

Some residents quoted by Reuters news agency said they were organising groups to defend their property.