Tunisia has banned a delegation from the European Parliament from entering its territory. This delegation composed of five members of the European Parliament's foreign affairs (AFET) committee, was due to start an official mission to the country on Thursday.

In a letter addressed to the European Union's delegation in Tunis, Tunisia's foreign affairs ministry said that the parliament's delegation would "not be authorized to enter national territory."

The parliament's foreign affairs committee has condemned the Tunisian authorities' decision and demanded a "detailed explanation."

"This conduct is unprecedented since the democratic revolution in 2011," the committee said in a statement. 

A spokesperson on behalf of the European Commission said on Thursday that the Tunisian government's decision "came as a surprise to us," but could not confirm whether it would impact the controversial migration agreement, the EU recently signed with Tunisia.

The delegation's visit intended to evaluate the current political situation in Tunisia after its fact-finding mission in April this year found "political backsliding on democratic standards and human rights" in the country. 

It was also due to assess the EU-Tunisia migration deal. The five MEPs were set to meet with NGOs, trade unions and opposition leaders, but had failed to secure meetings with the Tunisian government.