More than 1,000 migrants stranded for days at Budapest's main train station left the building yesterday, intent on walking to the Austrian border, according to an AFP journalist on the scene.

The huge crowd included people in wheelchairs and on crutches, as well as parents carrying children on their shoulders, all prepared to march 175 kilometres to the border.

Police watched the silent migrants walk through the Hungarian capital but did not intervene, the AFP correspondent said.

Prime Minister David Cameron said yesterday Britain will take in thousands more Syrian refugees amid growing pressure at home and abroad to address the crisis.

"Given the scale of the crisis and the suffering of the people, today I can announce that we will do more, providing resettlement for thousands more Syrian refugees," he told reporters on a visit to Lisbon.

Europe is facing a historic "moment of truth" over the huge influx of refugees and migrants arriving in EU countries, the European Commission's vice-president Frans Timmermans said Thursday.

Speaking on Kos, one of several Greek islands struggling to cope as thousands of people arrive from Turkey, Timmermans warned that if the EU fails to help refugees, Europe will be left to "the xenophobes, the extremists, who will destroy it."

At least 30 migrants are feared to have drowned off Libya after their dinghy began to sink, the International Organisation for Migration (IOM) said yesterday.

Some 91 survivors rescued by the Italian coastguard on Thursday said the boat had been carrying between 120 and 140 people when it began to deflate, sparking panic and tipping some people overboard.

Relatives mourn during the funeral of two Syrian toddlers, including three-year-old Aylan Kurdi, who drowned with their mother as they were trying to reach Greece, at the Syrian border town of Kobani. Photo: Reuters

Hungary's parliament yesterday introduced emergency anti-migration laws, in a tough response to the record number of refugees and migrants crossing the EU member's border as they try to reach western Europe.

The new measures include three-year jail terms for people climbing over the newly built razor wire fence on the border with Serbia, as well as new border "transit zones" to hold asylum seekers while their applications are being processed.

Meanwhile, refugees on the Greek island of Kos were attacked in the early hours of yesterday by "thugs" with bats, telling them to "go back to their countries", rights group Amnesty International said.