One in four Syrian refugees who comes to the UK this year could be taken in by Scotland, according to the SNP.

The party has called for more action from UK ministers and urged them not to close the doors to "wee boys and girls and mums and dads in Greece" and other European countries.

It came as the President of the European Commission Jean-Claude Juncker unveiled details of a plan for European states to accept an extra 120,000 refugees.

The UK, which rejects the idea of quotas, confirmed it would stay outside the Juncker proposals, which would operate within the European Union's common travel area.

Prime Minister David Cameron also came under pressure to defend his plans to accept 20,000 refugees over the next five years.

Critics warn this could mean that fewer than 4,000 come to the UK this year.

Scottish First Minister Nicola Sturgeon has already said that Scotland is ready to accept 1,000 refugees "as a starting point".

Mr Cameron hit back at critics, saying that there was no limit to the numbers who come this year, within the 20,000 ceiling.

He also twice suggested that refugees may not find a "warm welcome" in the UK unless the infrastructure necessary for them to integrate into society was created before they arrive.

Later in a Commons debate led by the SNP the party's group leader Angus Roberston called on the UK to think the unimaginable and take more and more refugees.

He also called on the Prime Minister not to abandon those fleeing the conflict in Syria just because they had already made it to Europe.

Mr Cameron has said that the 20,000 places offered will go to those currently in camps around Syria.

The Conservative Government said that it wants to remove incentives for people to attempt the dangerous journey to Europe.

Opponents have called on the government to loosen its approach, especially for unaccompanied children.

But Downing Street sources said they did not want to create perverse incentives for families to split up.

Mr Robertson called on Tory ministers to "rise to the challenge" of the "biggest refugee crisis ... since the Second World War".

He added: "We have already had a concrete suggestion from the Scottish Government that 1,000 refugees can be accommodated this year. If the UK total, which is 20,000 over five years, is 4,000 in a year, we are talking about the possibility this year of a quarter of all refugees in the UK being housed in Scotland. Surely the rest of the United Kingdom would not wish to be left in a position where not as much is being done."

He added that he was asking that the UK Government "should not close its mind to doing more, regardless of its politics, regardless those things that divide us we share as human beings a responsibility to refugees not just in camps in Jordan and Lebanon, but wee boys and girls and mums and dads in Greece, in Italy, in Austria, in Hungary, in Germany, in Sweden."

Mr Robertson, who is half German, also drew on his family history, telling MPs: "In 1945, 1946, 1947, the UK even accepted those who had been enemy aliens as refugees. I have much to be personally grateful for that as my mother was amongst those refugees."

The International Development Secretary Justine Greening told him that her government was working hard to make sure "we can cope with the people who are coming over and provide the kind of support that I know very personally they will need".