Hello, I'm Natalia Roston with the BBC news.

Smoke is billowing from the site of huge explosions in the Chinese port city of Tianjin, which killed at least 17 people and injured hundreds more. Images on social media show a scene of utter devastation. The authorities say the massive blasts were caused when a shipment of explosives being stored in a container detonated. Our correspondent John Subworth is in Tianjin, and reports from a destroyed dormitory building 100m from the site of the explosion.

"What I'm standing in is what was a dormitory for migrant workers. You can see roofing materials, these corrugated panels, lying everywhere. And some of the people here we've spoken to say there were a number of very serious injuries, just as you'd expect. Others, though, have come away unscathed, and are picking through the rubble, trying to salvage what they can. Other people sitting around in total shock, really, almost impossible to comprehend what has just happened to them. They have their lives completely turned upside-down."

China has allowed its currency to devalue for a third day running. The Central Bank set the guidance rate for the yuan 1% lower against the dollar. The fall in the currency has caused uncertainty on global financial markets. But the International Monetary Fund has welcomed the moves towards allowing market forces to have a greater role in determining the exchange rate. This week's decline in the value of the Chinese currency is the biggest in two decades. Juliana Liu reports.

"The yuan trades in a managed float, that means every morning, officials set a reference rate, a mid-point around which the currency is allowed to trade. Three days ago, the mechanism for setting that rate was effectively changed, allowing supply and demand more say in the exchange rate. The currency's subsequent weakness is a reflection of worries about the state of the Chinese economy."

Security forces in Myanmar remain outside the headquarters of the military-backed ruling party in the capital, after raiding the building on Wednesday night. No explanation has been given. But correspondents say that factions within the ruling party have been engaged in a power struggle in recent months. There've been disagreements between the country's president Thein Sein and the party's chairman over who should serve the next presidential term. Elections are planned for November.

South Korea has pardoned more than 6,500 prisoners, including the chairman of one of the country's biggest conglomerates, Chey Tae-won, chairman of the SK Group, has been imprisoned for two years after being convicted of embezzling more than 40 million dollars. President Park Gyun-hye announced the pardons as South Korea marked the 70th anniversary of the end of Japanese rule, following its defeat in the Second World War. She said she hoped the releases would help to forge a national reconciliation and boost the economy.

BBC news.

The United States' most senior soldier has suggested that the country should consider deploying troops with their Iraqi counterparts, if progress isn't made within made in the fight against Islamic State. The Army's Chief of Staff General Ray.Odierno said such forces would have a support, rather than a combat, role. He was speaking at his last news conference before retiring on Friday. The United States has more than 4,500 troops in Iraq, largely in an advisory capacity.

Members of the International Olympic Committee have praised Rio de Janeiro's preparations for next year's games, despite concerns about pollution in the bay where sailing and wind-surfing competitions will be held. IOC executives visiting the city said the level of pollution in the waters of Guanabara Bay is within international standards. The Committee's Executive Director C D said conditions would improve before the games began in a year's term.

"Thanks to the games, first, the awareness regarding the bay has been raised to an unprecedented level, which, in itself, is a good thing. Then there are a number of actions that have been undertaken. And from now on until the games, this would continue, equal barriers, equal goals, and different measures. So from now until the games, the quality of water will continue to be monitored and shall improve." More than 50% of sewage in Rio flows untreated into the bay.

The President of Guinea-Bissau, Bacai Sanhá, has dismissed the government, following a rift with the prime minister, Domingos Pereira. The two men are said to disagreed on issues including the use of aid money and the return to Guinea-Bissau of a former army chief.

Scientists say listening to music before, during and after an operation can help reduce anxiety for the patients need for pain relief. A new study found that music had a positive effect, even when the patient has been under general anesthetic.

BBC news.