JPMorgan Chase, the biggest US bank, has revealed a surprise trading loss of $2bn (£1.2bn) on complex investments made by its traders.

Overall, after accounting for other gains, losses at its chief investment office (CIO) are estimated to come in at $800m in the second quarter.

The Brazilian armed forces have begun an operation in a vast area of the Amazon to tackle drug trafficking, logging and illegal mining.

More than 8,500 troops are taking part in Operation Agata 4. They will be patrolling an area that stretches some 5,000km (3,100 miles) along Brazil's northern border.

The US president has described US Secret Service agents caught up in the Colombia sex scandal as "knuckleheads".

Speaking at a recording of an NBC chat show Mr Obama said the vast majority of Secret Service agents performed their duties with no hint of controversy.

Nine Peruvian miners trapped underground for nearly a week by a rockfall have been rescued.

They were met by relatives and President Ollanta Humala after emerging from the Cabeza de Negro mine in southern Peru on Wednesday morning.