The number of migrants and refugees arriving on Greece's shores has fallen this week due to poor weather but the flow will pick up again if the weather improves, the UN refugee agency UNHCR said on Friday.
Almost 400,000 people have already made the risky trip by boat to Greece this year, the bulk of the 520,000 who have crossed the Mediterranean, and 6,600 arrived on September 25 alone.
But the following day there were only 2,200 arrivals, and just 1,500 on Thursday, UNHCR said.
"Nevertheless, any improvement in the weather could be expected to bring another surge in sea arrivals," UNHCR spokesman Adrian Edwards told a regular UN briefing in Geneva.
"The current cooler, windy weather has made the crossing from Turkey to Greece even more perilous. On Wednesday there were four separate rescue operations on Lesvos in which 283 people were recovered," a UNHCR statement said.
UNHCR is planning for a total of at least 1.4 million migrants and refugees to flee to Europe across the Mediterranean this year and next, it said on Thursday.
"It's very clear it's a continuing very large scale emergency," Edwards said.
He declined to comment on whether UNHCR expected Russian air strikes in Syria to hasten or hinder efforts to end the war in Syria, which is the single biggest cause of the refugee crisis.