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.
US, Iran at odds on nuclear inspections, frozen assets in deal to end war
US President Donald Trump has stated on Tuesday that Iran had agreed to nuclear inspections into "infinity," while Tehran said it had made no such concession in negotiations, raising questions about the viability of their fragile peace deal.
Oman establishes temporary shipping corridor through Strait of Hormuz
Oman has coordinated with the International Maritime Organisation (IMO) to establish a temporary maritime corridor for vessels transiting the Strait of Hormuz, according to its local news agency.
Power cuts in France leave thousands sweltering amid scorching heatwave
Authorities in northern France were scrambling on Wednesday to restore electricity to thousands of homes hit by power cuts amid a blistering heatwave that has scorched much of western Europe for days.
Libya's eastern government bans entry of nationals from four African countries
Libya’s eastern-based government has banned the entry of nationals of four African countries on Tuesday, a decision a government source said was due to a "reorganisation of foreign nationals’ entry to Libya".
New Lebanon-Israel talks begin in shadow of US-Iran deal
Lebanon and Israel began a new round of talks on Tuesday in Washington, with Beirut determined to press ahead with direct negotiations even as they appear to be overshadowed by Iran's decision to make Lebanon part of its talks with the US.
