“The number of refugees is expected to reach 4.27 million in addition to 7.6 (million refugees) displaced inside Syria”, the statement added.

“This is the biggest refugee population from a single conflict in a generation”, said United Nations High Commissioner for Refugees Antonio Guterres in a statement.

UNHCR said a surge in new refugee arrivals in Turkey had pushed the total number of Syrian refugees in neighbouring countries to over 4,013,000 people. Syrians made up about a third of the 137,000 migrants who crossed the Mediterranean in the first half of 2015. The conflict, now in its fifth year, has killed more than 220,000 people. The four million milestone comes barely 10 months since the total of three million was reached.

“Worsening items are pushing rising amounts around Europe and extra afield, the vast majority stop in the country”, Guterres said. “We…” FILE – In this June 14, 2015, file photo, Syrian refugees cross into Turkey from Syria over and through a hole on the border fence in Akcakale, Sanliurfa province, southeastern Turkey. “In reality, the figure is even higher as it does not include more than 270,000 asylum applications by Syrians in Europe, and thousands of others not resettled in regional neighbours”, the report said.

The refugee crisis is the largest resulting from a single conflict in almost a quarter of a century.

The UNCHR has described the Syrian refugee crisis as the worst in nearly 25 years.

According to the agencies and their partner organisations, the shortfall has meant 1.6 million refugees have already had food assistance cut this year and 750,000 children are not attending school.

UNHCR said life for exiled Syrians was becoming increasingly hard.

Around 86 percent of all refugees living outside of camps in Jordan living below the poverty line of $3.20 per day, and 55 percent of Syrian refugees in Lebanon are living in sub-standard shelters, it said. Competition for employment, land, housing water and energy in already vulnerable host communities is straining the ability of these communities to cope with the overwhelming numbers and sustain their support to them.