Frontex has reported a total of 1.2 million illegal border crossings at the EU's external borders in the first ten months of this year, which is four times the 282 000 recorded for the whole of 2014.

More than 540 000 migrants have arrived on the Greek islands between January and October, which was 13 times more than in the same period last year.

Syrian citizens continue to be the largest share of arrivals, with the number of Afghans having significantly increased in recent weeks.

Despite the worsening weather conditions in October, more than 150 000 people crossed from Turkey into Greece, compared to less than 8500 in the same month last year.

As a direct knock-on effect, 500 000 illegal border crossings were detected in the first ten months at the external borders in the Western Balkans, mainly on the Hungarian and Croatian borders with Serbia.

Previously, migrants had arrived on one of the Greek islands in the Aegean Sea and then left to the EU to travel through Macedonia and Serbia.

With the construction of a fence at the Hungarian border with Serbia and tightened border controls, the migrants have started to cross the Croatian border with Serbia in record numbers since September.

As part of its efforts to aid Greece and the Western Balkans to deal with the unprecedented migratory pressure, Frontex has strengthened Operation Poseidon Sea and deployed 114 officers on Lesbos and other Greek islands to support the local authorities in identifying, registering and taking fingerprints of the new arrivals.

Frontex has also proposed to increase its presence at the Greek land borders with Macedonia and Albania as well as at Croatia's border with Serbia.

At the same time, migratory pressure on the Central Mediterranean Sea route has decreased with the number of people crossing from Libya into Italy having dropped by a half in October.

This was largely due to the shortage of boats available to smugglers, which has brought the number for the first ten months of this year down to 140 000 people, while the corresponding figure in the same period in 2014 was 155 000.