The European Commission on Wednesday urged Greece to speed up the processing of asylum-seekers as a jump in new arrivals in its already overcrowded island camps pushed the situation to

"unbearable" levels.

MEPs heard from EU officials that the basis of a controversial 2016 migrant deal with Turkey, to stem arrivals in Europe, remains valid.

But they also heard that the Greek island "hot spots" meant to host migrants while genuine refugees among them were identified, were breaking down as numbers far outstripped capacity.

She said a Greek asylum vetting process, taking months and in some cases years, leads to "severe" mental health issues among "trapped" migrants, including suicide attempts and self-harm -- not least among children.

Vazquez demanded an end to the Turkey deal and "an urgent and immediate evacuation of the people from the hotspots".

- 'Critical' -

But the head of the European Commission directorate handing migration issues, Paraskevi Michou, said that, while the situation in the main camps was "critical" and "unbearable", the accord should stand.

The Commission, she said, has asked Greece "to make it better, to have better proceedings -- to have assessment of the cases case-by-case, but have a system that works."

She admitted that the part of the deal with Turkey which would enable the EU to send back migrants not deemed to be refugees was not working and that arrivals this year were rising.

But she also drew attention to challenges faced by Turkey, which is hosting four million asylum-seekers, most of them refugees from neighbouring war-torn Syria.

"They do more or less 4,000 apprehensions every week of people who want to transfer from Turkey to Greece. What does it say? It says that the pressure is high," she said.

Greece's minister for citizens' protection, Michalis Chrisochoidis, drove home the point that his administration was overwhelmed.

"We cannot manage so many people when they all arrive at the same time -- we cannot do it," he told the MEPs.

Already, he said, there was a backlog of 68,000 asylum requests in Greece, with some applicants saying they have to wait three years for an interview to assess their case.

- Worrying 'rights issue' -

The EU's Asylum Support Office assisting Greece said it had registered or pre-registered 30,000 applicants this year.

The head of the European bloc's agency for fundamental rights, Michael O’Flaherty, confirmed that a trip he made to the Greek hot spots at the end of this month revealed the extent of the overcrowding.

"Overall there are 30, 000 migrants on the Greek islands in facilities with a capacity of 5,000," he told the hearing.

"We believe still that the hotspot concept remains valid -- if it works as it was originally designed," he said, adding that "urgent decongesting of the facilities" by transferring migrants to the Greek mainland was needed.

He added: "It's my personal view that the situation of migrants on the Greek islands right now is the single most worrying fundamental rights issue that we're confronting anywhere in the European Union."