Islamic State (Isis) has claimed responsibility for the terror attack in Manchester last night.
The terror group said one of its members had carried out the attack, which killed 22 people, including children, and injured dozens more.
A suicide bomber is believed to have detonated an improvised explosive device at an Ariana Grande concert in the Manchester Arena.
Greater Manchester police arrested a 23-year-old man in south Manchester earlier today.
Prime Minister Theresa May said in a statement: "All acts of terrorism are cowardly attacks on innocent people, but this attack stands out for its appalling, sickening cowardice – deliberately targeting innocent, defenceless children and young people who should have been enjoying one of the most memorable nights of their lives."
The UK's political parties have suspended election campaigning today.