Around 70,000 protesters took to the streets in Athens today, according to authorities, as two separate demonstrations were staged in the city while EU leaders discussed the plight of Greece in Brussels.
Four demonstrators and three policemen were injured in clashes, but none of the injuries are believed to be serious.
Police said seven people, out of more than 100 detained, had been arrested.
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Authorities have warned that the death toll is likely to rise as much of the building is yet to be searched.
The PM will sound out the possibility of new free trade agreements with Gulf states for once the UK has left the EU.
In the unexpected announcement on Monday, Mr Key said it was the "right time" to leave politics.