At least 42 inmates have been found dead at four prisons in the capital of Brazil's northern Amazonas state on Monday.
Authorities said the victims appeared to have been killed by "asphyxiation" and were discovered during routine inspections at the prison facilities.
Additional reinforcements have been dispatched to boost security, they added, without providing more details.
This comes a day after 15 prisoners were killed in gang clashes in the same city.
Saudi civil aviation extends suspension of operations at Riyadh airport
The Saudi civil aviation has extended the suspension of operations at King Khaled International Airport in Riyadh on Monday following attacks on the facility.
1 dead, 11 injured in Sunday's attack on Riyadh airport, says aviation authority
Saudi Arabia's Civil Aviation Authority has reported the death of a resident, with 11 others injured following the attack on King Khaled International Airport on Sunday.
Delhi closes metro stations as opposition plans march over voter list row
Delhi has closed six metro stations on Monday and imposed traffic restrictions as opposition parties plan a march to the Supreme Court over a controversial revision of voter lists.
Israeli fire kills 2 people in Gaza, medics say
An Israeli strike has killed at least two Palestinians in the southern Gaza Strip on Monday, health officials said.
Thailand flood death toll rises to 71
The death toll from floods in Thailand has risen to 71, with nearly 908,000 households affected across 51 provinces since mid-September, the country's Interior Ministry said on Monday.
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