The European Union has struck a tentative deal with Afghanistan to return an unlimited number of Afghan asylum seekers with a conference to start in Brussels aimed at securing international financial aid for the war-torn nation. 

EU officials, however, have denied that aid pledges would depend on the Kabul government accepting the return of tens of thousands of Afghans from an overstretched Europe.

"This agreement allows for the repatriation of failed asylum seekers from EU member states. There could be tens of thousands of them," Al Jazeera's Jennifer Glasse, reporting from Kabul, said.

"It allows planeloads of up to 50 failed asylum seekers [the EU] wants returned to Afghanistan, and that the Afghan government must accept them and repatriate."

EU member states last Thursday endorsed the plan to pave the way for signing the deal in the run-up to the Brussels aid conference starting on Wednesday. 

The European Council, which represents the 28 EU member states, said the deal reflects the commitment of both sides "to step up their cooperation on addressing and preventing irregular migration, and on the return of irregular migrants, who do not fulfil the conditions for staying in the EU".

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Like other parties to international treaties, the EU is legally obliged to admit people fleeing war and persecution, but can turn back people classified as economic migrants.

Al Jazeera's Naeve Barker, reporting from Brussels, said the deal had been seen "in some circles as something of a condition", and "perhaps Afghanistan's hand has been forced - largely because of the insecurity on the ground there - to agree to a situation that would see potentially tens of thousands of people returned".

Amnesty International's Horia Mosadiq said international and Afghan rights groups "were quite appalled at the secret deal", and many viewed it as "some sort of blackmail. 

"Yesterday, when I spoke with one of the officials in Kabul, he told me that it was a 'poisoned glass that we had to drink because of the future of our country'," she told Al Jazeera. 

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"It is concerning that there is no upper limit to the number of refugees that can be deported, and more concerning is the security situation in Afghanistan that is deteriorating every day.

"We already have more than 1.2 million internally displaced people, with over three million refugees living in Iran and Pakistan that are also in danger of being deported back to the country." 

The EU, faced with its worst migrant crisis since World War II, has already come under fire for a deal with Turkey to take back Syrian asylum seekers from Greece in return for billions of euros in aid.

EU officials last week denied linking aid to migrant returns after the leak of an EU memo in March suggested that financial pledges would be made in return for Afghanistan accepting 80,000 asylum seekers deported from EU countries.

One anonymous Afghan government told Al Jazeera the government "felt pressured" to sign the deal.

"They said it was a rather diplomatically put 'polite threat’, and that perhaps if it weren't signed before the Brussels conference, it could affect the level of aid that Afghanistan gets," said Al Jazeera's Glasse.

EU Commission spokesperson Maja Kocijancic declined to comment on the memo and said EU work to implement the deal will respect international standards.

Among those attending the aid conference formally starting on Wednesday will be US Secretary of State John Kerry, UN Secretary General Ban Ki-moon, Afghan President Ashraf Ghani, and European Council President Donald Tusk.

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Source: Al Jazeera News And Agencies