'Safety must be first at airports' says UK PM Cameron

Prime Minister David Cameron has said the safety of travellers must come first, after security was tightened at UK airports in response to US warnings of a "credible threat" from terrorists.

Officials in the US believe Islamist groups are developing hard-to-detect bombs that could evade routine checks.

In the UK, main airports including Heathrow and Gatwick airports say they are operating as normal.

Mr Cameron said it was right to take extra precautions.