Images of migrants crossing into Spain's North African enclave of Ceuta have fuelled support for far-right parties despite a sharp decline in irregular arrivals in Europe following tougher migration policies, EU Migration Commissioner Magnus Brunner said on Friday.

More than 72 000 people surged into the enclave from Morocco at the end of July, although most later left. Spain estimates 12 000 migrants remain in the tiny territory, including minors.

"We have the decreasing numbers, but images from Ceuta, of course, overshadow the actual successes and the actual facts and figures," Brunner told Reuters in an interview.

He said these images "fuel the far right", which was why "it is so important to return those people as soon as possible to show that we have control."

Asked about Commission President Ursula von der Leyen's proposal on Wednesday for an emergency framework to prevent "engineered and weaponised" mass movements of migrants, Brunner said the details would be discussed at the next EU Council meeting of member states. But "first of all, we have to implement the system we already agreed on," he added.

Anti-immigration sentiment has remained a potent political force across Europe since more than 1-million people, many of them Syrians fleeing war, arrived in the bloc in 2015. The surge has helped boost support for nationalist and far-right parties and pushed many governments towards tougher migration policies focused on deterrence and returns.

Brunner also defended the European Commission's decision to facilitate talks between EU member states and Taliban officials, as governments seek ways to return Afghans convicted of crimes in Europe. Rights groups criticised the move, saying it lent legitimacy to Afghanistan's Islamist rulers, put Afghans at risk and undermined core EU values.

"I think first and foremost, it's about European security and the security of the European citizens," Brunner said when asked how the bloc could ensure that deportees sent to Afghanistan would not face persecution or harm.