GENEVA -- The UN's refugee agency and its top human rights official warned European Union leaders on Friday that they had a duty to protect immigrants and tackle the conditions that force many people to flee to Europe.

"Europe should also be looking beyond its own borders to the countries of origin. That's where real solutions should begin," UN High Commissioner for Refugees Ruud Lubbers said in a message to the summit of EU leaders currently meeting in Seville, southern Spain.

"It is irrational for governments to spend millions of euros on reinforcing borders, various deterrence measures, custody and detention centers and numerous other domestic approaches, without simultaneously investing in solutions at the source of the problem," he added.

In her message to the two-day summit, which began on Friday, UN High Commissioner for Human Rights Mary Robinson said several human rights organizations had raised concerns about "gaps in the EU's integration policies", including immigrant detention, human trafficking, the return of undocumented migrants and asylum seekers, the treatment of migrant children and refugee protection.

"Migrants' rights are protected in international law," she said, adding that the countries of the 15-nation EU had made commitments on the protection of migrants, refugees and asylum seekers at the world conference against racism in Durban, South Africa, last year.

"I wish (EU) heads of state and government all the best in their deliberations in Seville and hope that the commitments made in Durban will contribute positively to their debate," Robinson added.