A protest broke out in the Moria migrant detention center on the Greek island of Lesbos Tuesday during a visit by the Greek migration affairs minister and a Dutch official.

A Greek official said Ioannis Mouzalas was at the camp with Dutch Junior Justice Minister Klaas Dijkhoff when migrants began shouting "freedom" and "open the borders," and banging metal objects. The official, who spoke on condition of anonymity in line with department regulations, said the situation was tense.

The ministers left the camp and protesters, mainly unaccompanied teenagers, started fires by setting rubbish ablaze. A riot police contingent was sent to Moria but was waiting outside and had not intervened, police said, adding that staff had left the camp and were waiting outside.

The Moria camp was converted into a closed detention center after a European Union-Turkey deal aiming to stem the flow of refugees and migrants into Europe. Under the agreement, those arriving on Greek islands from March 20 onwards are detained and face deportation unless they successfully apply for asylum in Greece.