The UN Refugee Agency on Thursday called for an urgent investigation after the freezing to death of irregular migrants who had their clothes taken and were pushed back at the Greek border.

With the discovery of seven more bodies in Turkish city Edirne's İpsala district, the number of irregular migrants who froze to death since Wednesday rose to 19.

UNHCR spokesperson Shabia Mantoo described the freezing to death of irregular migrants as "heart-breaking" in a statement to Anadolu Agency.

"We are shocked and deeply saddened by the news," said Mantoo, explaining that the refugee agency is following up on the deaths with all the parties concerned.

"We call for an urgent investigation. We reiterate our call to ensure that the lives, rights, safety, and well-being of refugees and migrants are protected and put first," said the official.

Turkiye and international human rights groups have repeatedly condemned Greece's illegal practice of pushing back asylum seekers, saying it violates humanitarian values and international law by endangering the lives of vulnerable people, including women and children.

In a tweet, UN Secretary General Antonio Guterres said: "Every person searching for a better life deserves safety and dignity. We need safe, legal routes for migrants and refugees."/aa