Heavy summer rains, which meteorologists attribute to a series of low pressure systems that originated in the southern Atlantic Ocean this month, have wiped out crops in Peru and swollen rivers in northern Chile.
Anti-personnel and anti-tank mines laid around Chile`s Lluta river watershed in the 1970s, when tensions ran high between the two countries, have also surfaced, officials said.
As a precaution, Chile blew up four mines found by the highway on Monday that links the Peruvian city of Tacna with Arica in Chile. Officials were worried that more mines might wash down to the road.
"The water is bringing other bombs, so we are monitoring this every two hours to see what will happen," Ximena Valcarce, a regional official in Chile, told the La Tercera newspaper.
The border could reopen on Tuesday if the mines washing down towards the road. The two cities rely on the highway to trade everything from food to medicine.
Though trade and investment flows between the two fast-growing economies are strong, Peru and Chile have sparred over their border since Chile won the 1879-1883 War of the Pacific.
Peru has taken a maritime territory dispute with Chile to the International Court of Justice in The Hague.
Chile evacuated workers and residents near the Lluta river.
Flooding has been worse in Peru, where more than 4,500 homes and
99 hectares (245 acres) of crops have been destroyed this month from the desert coast to the Amazon lowlands, according to civil defense authorities.
Meteorologists say Peru may have one of its wettest summers ever.
"These (low-pressure) systems are altering the entire Peruvian atmosphere and this is why the rains are above average," said Nelson Quispe of Peru`s national weather service. (*)