Hello, I'm Nil Nunes with the BBC News.

The British Prime Minister, David Cameron, is preparing for a day of frantic diplomacy in Brussels, as he tries to win support from the twenty-seven other European leaders to achieve the reforms he wants. The deal would pave the way for a referendum in the U.K. on Britain's membership of the E.U. One potential sticking point is the concern that changes to welfare payments designed specifically for Britain could be adopted later by other member states. Alex Russell has this report.

“For the next two days, lawyers will be on hand to hammer out legal and technical changes to the proposed U.K. deal. But it will be for E.U. leaders to resolve the remaining political differences. There is no final agreement on the precise language, governing equality between countries inside and outside the Euro Zone, or on how changes to welfare payments for E.U. migrants in the U.K. would work and for how long they could be enforced.”

Government officials in the United States say that President Obama will make a historic visit to Cuba in the coming weeks, marking a turning point in the relations between the two countries after more than half a century of hostility. John Sophia reports.

“The speed with which this relationship has thawed has been nothing short of breathtaking. It was just over a year ago when Presidents Obama and Raul Castro said they wanted to put the hostility of the Cold War behind them. Last summer, their respective embassies reopened in Washington and Havana. And earlier this week, it was announced that instead of there being the occasional charter flying into Cuba from the U.S., commercial aviation would resume, with 110 flights a day from across America to the Caribbean island.”

Pope Francis has highlighted the plight of people who are forced to migrate. He was celebrating mass with thousands of worshippers, who had gathered in the Mexican border town of Ciudad Juarez. More from Kitty Watson.

“Tens of thousands of people came to watch the border mass, the Pope's final event and the culmination of the trip that was all about meeting people on the margins. Just a few moments before, the Pope had prayed in silence for the thousands of people who'd lost their lives trying to cross into the United States. This was a hugely symbolic mass, a gesture to unite two sides. As a Latin American and a child of immigrants, this is a subject close to his heart.” Kitty Watson.

The State Department in the United States says it is aware that radioactive material is missing from a storage facility near the southern Iraqi city of Basra. Iraq reported the theft of up to 10 grams of iridium isotope used to treat cancer to the International Atomic Energy Agency, late last year. Iraqi officials say the material, which poses a risk of bodily and environmental harm, could also be used as a weapon if acquired by the Islamic State militant group.

World news from the BBC.

In Egypt, the last remaining centre for the treatment of torture victims has been ordered to close by the authorities. The Aida Seif Centre has documented human rights abuses and provided counselling to victims of torture since 1993. But it has been given until next week to shut down. The authorities said it had breached Health Ministry regulations.

Polls have opened in Uganda's presidential and parliamentary elections. President Yoweri Museveni is widely expected to win again, extending his tenure into a fourth decade. He faces seven challengers. Several polls indicate that he will win the fifty percent of the vote needed to avoid a runoff. The main opposition candidate, Kizza Besigye, has already said that he does not expect the vote to be free and fair.

Venezuela has increased the price of petrol, which is practically free in the oil-producing country, for the first time in almost twenty years. Announcing several measures aimed at fighting Venezuela's economic crisis, President Nicholas Maduro said a litre of premium petrol would go up from the equivalent of one U.S. cent to ninety-five cents.

Scientists studying a tiny sea snail have discovered that it swims using the same movements as flying insects. The so-called sea butterfly has two wing-like appendages, where most snails have a single foot. The BBC's Johnason Webb now reports.

The sea butterfly looks like a transparent, gelatinous snail, with slimy wings sprouting from the opening of its shell. But instead of using those appendages as paddles, like the most types of swimming plankton, this tiny animal genuinely appears to fly under water. Tracking its movement in minute detail, researchers found that the snail's wingtips trace out a figure of eight to generate lift, just like of those of an insect. It may not float, but the sea butterfly does apparently swim like a bee.

That's the BBC News.