Latest: Hostage-takers slit throat of elderly priest in Normandy church; one person arrested

Latest: One person has been arrested in France after an attack on a church in which an elderly priest was killed.

Update 3.15pm: One person has been arrested in France after an attack on a church in which an elderly priest was killed.

Update 2.04pm: The so-called 'Islamic State' group has claimed responsibility for the attack in France in which two people killed an 84-year-old priest.