Prime Minister David Cameron has tweeted:
I'm appalled by the murder of a Palestinian teenager. The loss of four boys this week is a terrible reminder of the need for lasting peace.
More top news
An investigation is underway after a woman was sexually assaulted and train station staff spat at by a boy thought to be about 11-years-old.
Former residents of the Chagos Islands have lost their latest legal challenge at the Supreme Court.
The gun and bomb attack at Istanbul's Ataturk Airport is the latest in a series of deadly incidents in Turkey this year.