BBC News with Sue Montgomery.

Nato has called on Russia to step back from confrontation over eastern Ukraine. Speaking during a Nato summit in Wales, the organisation's Secretary General Anders Fogh Rasmussen said leaders were sending a clear message that the alliance stood with Ukraine. From the summit here's Jonathan Marcus.

In public Nato's message is one of resolve - full backing for Ukraine's sovereignty and territorial integrity combined with strong criticism of Russia's policies. But there's another message too - essentially telling Ukraine that any practical help that Nato may give Kiev will be limited and will be more a prospect for the medium term. What matters now is to deescalate the crisis. There'll be no Nato weapons or Nato troops. What the alliance is doing is essentially re-emphasising its defence lines on Ukraine's western border. If this means that Kiev has to make concessions to Moscow, then so be it.

In Ukraine itself pro-Russian separatist forces are advancing on the south-eastern port city of Mariupol. The city is the last major urban centre in the region still in government hands. Both Kiev and the rebels have said that a deal to end the conflict could be signed on Friday. Fergal Keane has been watching the fighting.

I'm on the last Ukrainian position outside Mariupol. Rebel forces are advancing towards here from the east. The men here said that they had to retreat a couple of hours ago because of the presence of what they said were Russian tanks attacking them.

The local governor Serhiy Taruta told me his forces would hold the city if the rebels made a direct attack. On the rebel side in the town of Yasynuvata the desire for peace among civilians we met was overwhelming.

Nato leaders have also been discussing how the alliance should respond to the threat posed by the militant group Islamic State in Iraq and Syria. So far no Nato member state has joined the United States in conducting air strikes against the group. The British prime minister has said he will urge members of the alliance to stop paying ransoms to the militants.

A judge in the United States has found the oil giant BP "grossly negligent" over the Gulf of Mexico oil spill in 2010. Shares of the company fell sharply after a federal judge in New Orleans ruled that BP's reckless conduct had led to the biggest offshore oil disaster in US history. Here's our business correspondent Theo Leggett.

This ruling will come as a blow to BP, which has consistently denied accusations of gross negligence. It means that the energy giant could face fines up to four times higher than would otherwise have been the case, potentially increasing the bill it faces by about $15bn. However, much will depend on how large the court deems the spill to have been, a point of which it has not yet ruled. BP insists that the judge's finding is not supported by the evidence at the trial and says it will immediately launch an appeal.

BBC News.

The United Nations says about 120 million girls around the world, slightly more than one in ten, have been either raped or sexually insulted by the age of 20. The UN children's agency Unicef found that in 2012 alone nearly 100,000 children and teenagers were murdered, most of them in Latin America and the Caribbean.

The former governor of the US state of Virginia Bob McDonnell and his wife have been convicted of corruption. Mr McDonnell,who left office in January, was once a rising star of the Republican Party. But a federal jury concluded that he and his wife, who say they are now estranged, used his office to endorse the healthcare products of a businessman in return for lavish gifts. They are due to be sentenced in January.

One of America's best-known comedians, Joan Rivers, has died aged 81. She'd been in hospital in New York for the past week since suffering a heart attack. Nick Bryant reports on her life.

Joan Rivers was known for her lacerating and outrageous humour that took aim not only at Hollywood celebrities but also herself. Her extensive plastic surgery provided a rich source of laughs. She first rose to prominence in the mid-1960s as a writer and then regular guest on Johnny Carson's famed Tonight Show and went on to become the first woman to have a late night chat show of her own. But in recent years she gained a new following amongst younger viewers by hosting a show, Fashion Police, and becoming a red-carpet commentator, the role seen perfectly tailored for her trademark form of comedy that cut others and herself to shreds.

Reports from Belarus say a teenage boy has been threatened with a fine for nominating the country's autocratic President Alexander Lukashenko to do an ice-bucket challenge. Millions of people around the world have poured buckets of icy water over their heads to raise money for charity and have challenged others to do the same.

BBC News.