Some 3,700 have died or gone missing trying to cross the Mediterranean

Million mark reached with arrival of more than 4,100 into Greece on Monday

More than a million migrants have now crossed into Europe this year - more than four times the total for 2014, it has been revealed.

Half of those arriving were Syrians fleeing the war, another 20 per cent were Afghans, and seven per cent were Iraqis, according to agencies monitoring the flow.

More than 800,000 arrived by sea in Greece while 3,700 have died or gone missing trying to cross the Mediterranean.

More than a million migrants have now crossed into Europe this year - more than four times the total for 2014, it has been revealed

Half of those arriving were Syrians fleeing the war, another 20 percent were Afghans, and seven percent were Iraqis, according to agencies monitoring the flow

The figures were revealed by the International Organisation for Migration, which said the million mark was exceeded on Monday.

More than 820,000 crossed into Greece from Turkey, including more than 455,000 from Syria and over 186,000 from Afghanistan, the IMO said.

The 162-country intergovernmental agency says the arrival of more than 4,100 people into Greece on Monday put the annual total over 1 million.

The figure includes more than 34,000 arrivals by land from Turkey into neighboring Greece and Bulgaria, or only about 3.5 percent of the total this year.

Most of the deaths this year came on the Mediterranean between north Africa and Italy, IOM said.

But some 706 people are known to have died trying to cross the Aegean between the Turkish coast and a number of nearby Greek islands.

IOM says its figures are pulled together through a combination of people registered and counted, as well as estimates given the sheer numbers.

A painting by English graffiti artist Banksy is seen at the entrance of the Calais refugee camp in France, in Calais, northern France

The figure includes more than 34,000 arrivals by land from Turkey into neighboring Greece and Bulgaria, or only about 3.5 percent of the total this year

The agency compiles figures provided by law enforcement in countries like Italy and Greece, and its own monitors carry out a real-time count on the Greek islands and in Italy.

The U.N. refugee agency UNHCR is planning for arrivals to continue at a similar rate in 2016, but IOM spokesman Joel Millman said it was impossible to forecast future numbers.

'So much is in the balance, the resolution of the Syrian war, and the disposition of the European border protection moves that are being contemplated,' he said.

'We never thought it would reach this level. We just hope people are treated with dignity.'

The record movement of people into Europe is a symptom of a record level of disruption around the globe, with numbers of refugees and internally displaced people far surpassing 60 million, UNHCR said last week.

'I don't understand why people are insisting that this is a European problem. This is a global issue,' Michael Moller, director of the U.N. office in Geneva, told a news conference on Tuesday.

More than 800,000 arrived by sea in Greece while 3,700 have died or gone missing trying to cross the Mediterranean

The migrants' crisis, Europe's worst since World War II, has forced European governments to scramble to cobble together a response, and caused rifts among EU member states

The U.N. refugee chief Antonio Guterres called on Friday for a 'massive resettlement' of Syrian and other refugees within Europe, to distribute many hundreds of thousands of people before the continent's asylum system crumbles.

He called for European countries to recognise the positive contributions made by refugees and migrants and to honour what he said were 'core European values: protecting lives, upholding human rights and promoting tolerance and diversity.'

The migrants' crisis, Europe's worst since World War II, has forced European governments to scramble to cobble together a response, and caused rifts among EU member states.

Germany and Sweden have been among the most welcoming, and some less-wealthy eastern European countries have erected border fences in an attempt to block the flood of migrants and refugees.