Germany is expecting one million migrants this year - 200,000 more than previously estimated, Angela Merkel's deputy has said.
In a letter to party members, the country's vice chancellor, Sigmar Gabriel, said: "Everything points to the fact that we won't have 800,000 migrants as has been predicted by the Interior Ministry, but one million."
He also called for other EU nations to take their fair share of refugees, and warned a "common European effort" to tackle the crisis is badly needed.
With the Schengen system of border-free travel through much of the continent under increasing pressure, the European Commission is to outline plans to distribute 160,000 refugees across 22 EU member states over the next two years.
Several countries are opposed to the quota policy.
The UK is not involved in the scheme and instead is planning to accept vulnerable and displaced people from refugee camps in nations bordering Syria.
Earlier today, David Cameron visited one such refugee camp in Lebanon's Bekaa Valley to see the impact of the humanitarian crisis "at source" days after vowing to take in 20,000 refugees over the next five years.