David Cameron has visited camps in Lebanon and Jordan to meet Syrian refugees who have fled their country's civil war.
The Prime Minister has called on other EU countries to "step up to the plate" and follow Britain's lead by funding refugee camps around Syria.
Mr Cameron said there was a "direct connection" between shortfalls in aid for camps in Lebanon, Jordan and Turkey and the influx of migrants into Europe.
Germany has halted rail traffic arriving from Austria according to a spokeswoman for Austrian rail company OeBB, quoted by the Reuters news agency, and has reintroduced border controls.
The situation in the other direction - from Germany to Austria - was not immediately clear.
German newspaper Bild also reported on Sunday the authorities were planning the temporary reintroduction of border controls in response to the refugee crisis.
On a visit to Jordan, David Cameron says that the EU must "follow Britain's lead" and fund more refugee camps around Syria.
The prime minister has insisted the UK will not participate in plans to redistribute 160,000 refugees who have arrived in Europe.
Train traffic with Austria suspended as German authorities seek to reduce the number of asylum seekers arriving in the country.