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.
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Police have been forced to close down motocross event near Sedgefield after one rider was killed and another seriously injured.
A woman hit by police gunfire during a counter-terrorism operation has been arrested after being released from hospital.
Police have been granted extra time to question a man who is being held on suspicion of planning a terror attack.