Just days before Bahrain's most prestigious international sporting event, the Formula 1 Grand Prix, security forces are reported to have used stun grenades to disperse anti-government protesters at an exhibition about the race. The clashes saw the security forces chase the demonstrators, who included the daughter of an activist who's been on a hunger strike for 70 days.

The Guinea-Bissau military leaders who seized power last week say they have agreed a two-year transition period before presidential and parliamentary elections are held. The agreement with the main opposition parties confirms the dissolution of parliament and the creation of a national transitional council, which will name an interim government. On Tuesday, the country was suspended from membership of the African Union until constitutional order is restored.

Researchers in Britain have published a study that they suggest could change the way in which breast cancer is treated. The study by Cancer Research UK divides breast cancer into at least 10 new categories. The lead researcher Professor Carlos Caldas said it could lead to better treatments.

"I think that of course this is a very important advance and it's a big step forward by having a much more precise assignment of a woman to a given sub-type of breast cancer that we will then have much more tailored treatment that is targeting the particular type of breast cancer that each woman will have."

The American television presenter Dick Clark, whose show American Bandstand helped rock 'n' roll music reach a mainstream audience, has died aged 82. He was also the long-standing host of the annual New Year's Eve broadcast from Time Square in New York.