Germany is to restrict the number of entry points for migrants arriving via Austria, in a bid to control the flow as thousands cross into Bavaria daily.

It says it has reached agreement with Austria on five crossing points on the 800km (500-mile) border.

Authorities in Bavaria have complained a lack of co-ordination with Austria is hampering efforts to aid new arrivals.

Many others continue to make their way via Greece, in freezing temperatures, hoping to get asylum in Germany.

Meanwhile, more than 20 migrants - many of them children - have drowned in more boat sinkings in Greek waters while they were trying to reach European Union countries via Turkey.

Greek officials said 19 people had died and 138 were rescued near the island of Kalymnos.

Three others died off Rhodes and three were missing. Six were rescued there.

And the Spanish coastguard called off the search for 35 migrants missing at sea the day after their boat was shipwrecked en route from Morocco.

Fifteen migrants were rescued alive from the vessel and the bodies of four others were found.

New influx

A spokeswoman for Germany's interior ministry told AFP news agency that the new rules on entry points would go into effect immediately.

"We would like to have a more orderly procedure," she said.

A senior Bavarian politician said that under the agreement, 50 migrants an hour could cross into the state at the five agreed points.

Earlier this week, German Interior Minister Thomas de Maziere accused Austria of transporting refugees to the German frontier at night, leaving them there unannounced.

Federal police spokesman Heinrich Onstein has said everything was being done to prevent the migrants from having to sleep outdoors.

He said the problem had been that "we do not know how many people will arrive, and at which border post".

However an Austrian police spokesman dismissed such accusations as a "joke", given that Austria was receiving 11,000 people a day just at the Spielfeld crossing from Slovenia.

Germany expects at least 800,000 asylum seekers this year - some estimates put it as high as 1.5 million. That is at least four times the number who arrived last year.

Last Wednesday, more than 8,000 migrants arrived in Bavaria, German police said.

And last weekend authorities in Passau - a major transit hub for asylum seekers - said they had been overwhelmed by a new influx of some 15,000 people who arrived from Austria.

Several hundred spent a night out in the cold on the Austrian side of the border before reaching Germany, as the Austrian authorities said they had run out of beds for them.

The UN estimates that more than 700,000 migrants have crossed to Europe by boat so far this year - many of them refugees from war-torn Syria. The approach of winter has so far done little to slow the flow.