Tunisia has barred entry to a delegation from the European Parliament after some EU lawmakers criticized a deal Brussels struck with Tunis to stop migration, officials said on Thursday.

Legislators from the parliament's foreign affairs committee were due to head to the North African country on Thursday on a fact-finding mission.

Tunisia's Foreign Ministry confirmed on Thursday that the lawmakers would not be allowed entry due to "multiple reservations" about the visit.

"It is both astonishing and exceptional," MEP Mounir Satouri, a member of the delegation, told AFP.

"Never in at least 20 years has a regime allowed itself to refuse an official delegation from the foreign affairs committee and to say that even if we made the trip we would be turned back at the border."

The incident comes after the European Union inked a memorandum of understanding in July with Tunisia aimed at curbing irregular migration across the Mediterranean.

Under the deal -- pushed strongly by EU member Italy -- Brussels has promised potentially hundreds of millions of euros in financial support for the government in Tunis.

Tunisia is a main hub for thousands of migrants seeking to make the risky sea crossing to Europe.

In a debate this week, some MEPs complained about the deal that the EU had struck with the Tunisian government, which has been accused of reportedly abusing migrants from sub-Saharan Africa.

"This memorandum must be revised as it fails to address all concerns related to human rights, including the rights of migrants and asylum seekers, as well as the continued deterioration and deepening of the crackdown on opposition," the socialist S&D grouping said.

But the European Commission, the EU's executive arm, defended the agreement in parliament, saying it reinforced cooperation with a key partner.

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