Hello, I'm Tom Sandars with the BBC News.

The challengers for the US presidency have been addressing large rallies as they try to maximize their support on Super Tuesday. Eleven US states are choosing Democratic and Republican Party candidates for November's election. The Republican Donald Trump and the Democrat Hillary Clinton are hoping wins today will allow them to pull decisively away from their rivals. James Cook reports. “Polls suggest Donald Trump will sweep the board in almost all of the 11 states which are in play despite the hostility of many people inside his adopted party. Having built his support on divisive rhetoric about banning Muslims from entering the US and building a wall on the Mexican border, Mr. Trump today tries to present himself as the unity candidate. The exception to Mr. Trump’s expected dominance may be here in Texas, the home of Senator Ted Cruz who insists he is the only credible conservative alternative to the property tycoon, a claim disputed by another Senator Marco Rubio of Florida.” Mrs. Clinton’s only rival for the Democrats' nomination Bernie Sanders will be hoping to win in his home state of Vermont.

NATO's most senior commander in Europe has accused Russia of helping the Syrian government to create a refugee crisis deliberately as a weapon of war. General Philippe Breedlove told a Senate Committee in Washington that he could see no reason for Moscow and Damascus to use indiscriminate weapons against civilians in Syria other than to displace people. “The Russians are using almost no precision weaponry. Their weaponry is imprecise and dropped in a large quantity and again I don't know what military utility that would have other than to get people displaced and on the road and into someone else's problems there.”

The Head of FBI has accepted that forcing Apple to unlock an iPhone linked to aterror attack could set a legal precedent. James Comey told a congressional committee that Apple's iPhone encryption stopped law enforcement agencies from gathering evidence. Apple says creating software to unlock the phones would weaken the security of hundreds of millions of devices.

Police in Brazil have arrested the Vice President of Facebook Latin America saying the social media company has refused to cooperate in a drugs trafficking investigation. The authorities have been seeking information from the company’s phone messaging service What's App. Julia Carneiro reports. “Diego Dzodan was detained at his home in Sao Paolo accused of violating a Brazilian law on organized crime by failing to hand over data from What's App. If he's convicted of preventing or hampering investigations involving criminal organizations, he could face between three and eight years in prison. In a statement, Facebook described the detention as extreme and disproportionate.” You're listening to the latest world news from the BBC.

The Bolivian President Evo Morales has begun legal action against former girlfriend demanding his son he thought to have died nine years ago. The woman Gabriel Zapata has told Mr. Morales the boy died in infancy. But one of her relatives now says the child is alive and lives in an undisclosed location in Bolivia.Mr. Morales says Ms. Zapata has been given five days to present the boy to the authorities.

Officials in Jordan say the security forces have killed several militants during raids to arrest suspected Islamists in the northern city of Irbid near the border with Syria. The government described it as one of the largest sweeps against hardline Islamist groups in recent years.

Scientists say they've identified for the first time a gene responsible forgery hair. The researchers say the gene called IRF4 is involved in regulating melanin the pigment being hair color, as well as the color of the skin and eyes. One of the scientists Dr Kaustubh Adhikari from University College London says further research could make it possible to target proteins responsible for graying. “Wethink that eventually you could have a bill or you could have a lotion for yourskull about something that you might use for this purpose. That's all speculative in the future. We have to do much more study before we can do that.”

Police in the Philippines say a gunman has shot and wounded an influential Saudi Arabian preacher who had just left a university lecture. Sheikh Aaidhal-Qarni was attacked in the southern city of Zamboanga by a man who ran out of the crowd. The police shot the attacker dead. Sheikh al-Qarni's injuriesare not life threatening.

Top American baseball team The Tampa Bay Rays will play an exhibition match against the Cuban National Team in Havana during President Obama’s historic visit in three weeks’ time. The race will become the first Major League side play in Cuba since 1999. BBC News.