FBI agents zeroed in on how the Boston Marathon bombing was carried out – with kitchen pressure cookers packed with explosives, nails and other lethal shrapnel - but said they still did not know who did it and why.

US authorities are to maintain “enhanced security” at transport hubs as the nation struggles to make sense of the bomb attack on the Boston Marathon.

A 29-year-old restaurant manager has been identified as one of three people killed in the bombing at the Boston Marathon.

Militants freed a Filipino truck driver after the Philippines government gave in to their demands to withdraw troops from Iraq to prevent the beheading of the 46-year-old father of eight who had been held captive for two weeks.