The United Nations has warned that the recently drawn up deal between the European Union and Turkey to ease the migrant crisis might be illegal as it violates long-cherished principles on human rights. Under the pact, the EU would push refugees back to Turkey, which will receive political and financial support in exchange.

The deal is a product of the EU-Turkey summit held in Brussels on Monday. Turkish Prime Minister Ahmed DavutoÄŸlu suggested the "quick fix," under which every Syrian refugee or migrant who makes his way to Greece will be forcibly sent back to Turkey. More specifically, for every Syrian returned to Turkey, EU would accept another. The refugee accepted by the EU will then be assigned to a member state through a quota system.

United Nation's refugee agency (UNHCR) strongly opposed the agreement, arguing that it is tantamount to a violation of fundamental human rights.

"The collective expulsion of foreigners is prohibited under the European Convention of Human Rights," said UNHCR Europe regional director Vincent Cochetel, via Al Jazeera. "An agreement that would be tantamount to a blanket return of any foreigners to a third country, is not consistent with European law, is not consistent with international law."

The "one-for-one" deal comes with a bargain that will be advantageous to Turkey. Compliance with the agreement means Turkey will receive more funding to sustain the refugees returning to the country, which is estimated at around €6 billion. According to Straits Times, the EU-Turkey deal also grants faster approval of visa-free travel for Turks to Europe as well as expedites the discussions regarding Turkey's long-stalled EU membership.

Meanwhile, NATO will be allowed access into Turkey's territorial waters to facilitate the transfer of refugees.

Human Rights Watch refugee rights director Bill Frelick commented that the deal puts the European Union's integrity and values at stake.

In response to the criticism against the deal, Turkey has promised to comply with international law and treaties. According to a senior Turkish government official, the UNHCR will also assist in implementing the agreement.

"UNHCR will certainly not be excluded on any work conducted between Turkey and the EU. UNHCR will take part in the execution and the implementation," the official, who refused to be named, told Reuters.

Turkey is looking at a May 1 deadline to complete measures and other preparations to accommodate the influx of refugees and migrants once the deal takes effect. Among the measures taken are the passage of the personal data security law and introduction of biometric passports.