The European Commission is set to recommend granting visa-free travel for Turkish citizens inside the Schengen area, despite unease among some MEPs with one branding it a "huge error of judgement."
The change could take effect from July, but first it requires approval by the European Parliament and member states.
On Wednesday, the Commission opened the way for a decision on visa-free travel under the understanding that the Turkish authorities will fulfil, as a matter of urgency, its visa liberalisation roadmap.
EU officials insist that Turkey has yet to meet some key EU criteria.
The visa deal was offered in return for Turkey taking back migrants who crossed the Aegean Sea to Greece.
The EU fears that without this deal, Turkey will not control migration.
European visa-free regulations are limited to holders of biometric passports, which Turkey has not yet introduced.
But on Wednesday, Turkish Foreign Minister Mevlut Cavusoglu said Turkey was on the verge of completing the necessary technical work, including on passports.
He said, "If there are shortcomings, this is a process like EU membership, and these shortcomings can be overcome with Turkey's determination in the period ahead."
Freeing up visa rules for Turkey, a Muslim country of 79 million people, is a contentious issue among EU states and MEP reaction to the announcement was swift, with many critical.
EPP leader Manfred Weber warned, "There must be no watering down of the rules on visa liberalisation for Turkey. It is hard to understand why the Commission is now proposing visa liberalisation despite Turkey not meeting all the criteria. The European Parliament is independent and obliged to the citizens of Europe only."
The German deputy added, "We will take all the time we need for a thoroughly detailed examination and discussion of the visa liberalisation issue. Parliament should vote on visa liberalisation only if Turkey meets all the criteria and after the EU ministers have thoroughly reviewed the situation. It is very positive that the European Commission, after our insistence, has accepted an emergency mechanism to stop and suspend visa liberalisation in cases of abuse."
Elsewhere, ECR group home affairs spokesperson Timothy Kirkhope said, "It is simple; the EU has rules, and they were not made to be broken. Either Turkey objectively meets all of the criteria for visa free travel, or it doesn't."
He went on, "The Commission's assessment is intended to keep the migration deal on the road for another few weeks. However, visa liberalisation should never be a bargaining chip or a reward offered to countries in the hope they will help us with our migration problems. The ECR has a number of serious concerns about the EU-Turkey deal as a whole, and the price that some EU leaders seem willing to pay in order to keep it going.
"Even if Turkey meets the criteria, there will be significant political obstacles. There are legitimate concerns about the political, and security situation that Turkey finds itself in.
"A failure to properly consider the impact of visa liberalisation might buy some time for this deal, but it could lead to new problems in the future. If the EU is to find itself better prepared in the future, then it needs to start planning for the challenges of tomorrow, and not just the problems of today."
The British Tory deputy said, "That is why the EU needs to make sure that as soon as possible, the EU and the Schengen area adopt an effective entry and exit system as proposed by the Commission in April. Such a system will help protect the EU's internal security and external border, increase information sharing across the EU, and address potential problems with over-stayers.
"It will also give confidence to EU citizens and governments that visa liberalisation is a positive thing for the EU economy, and not just another potential problem heading down the road."
Further comment came from UKIP's Nigel Farage who said, "This is a huge error of judgement by the Commission. Turkey moves a step closer to EU membership and the British electorate move a large step closer to Brexit.
"The chaos from the beaches of Greece has evidently moved to the corridors of Brussels. The EU has rolled over to the blackmail from President Erdogan.
"Turkey is a country with a terrible human rights record, accused of helping ISIS and mistreating minorities. It is too big, too poor and too different from us and I certainly do not want the UK to be in a political union with Turkey."