EU leaders have agreed to send 40,000 migrants from Italy and Greece to other member states over the next two years, but the UK has opted out of taking them.
The number due to be sent to each country has not yet been decided, and countries are not obliged to accept their quotas under the voluntary system.
Hungary, which has accepted a huge number of immigrants in recent years, and Bulgaria, one of the EU's poorest member state, will both be exempt.
The decision was made on Thursday at the two-day EU summit being held in Brussels. Donald Tusk, President of the European Council, called on EU member states to share the burden:
Leaders agreed that 40,000 persons in need will be relocated from Greece and Italy to other states over the next two years. Interior ministers will finalise the scheme by the end of July.
Increasing numbers of migrants have been arriving on Europe's shores recently – since the start of this year, UN figures show that 62,000 and 63,000 migrants have arrived in Italy and Greece, respectively.
They are arriving mainly from African countries including Eritrea, Somalia and Nigeria.