The United Nations agency that is responsible for Palestinian refugees warned Monday that the Gaza Strip will not be viable if population growth continues under closure.

Robert Turner, operations director of the UN Relief and Works Agency (UNRWA), said at a news conference here that the population in Gaza will increase to over two million by 2020.

The Gaza Strip's current population is 1.6 million.

The population growth will be accompanied by a slow economic growth resulting in difficult living conditions in the Strip, Turner said, adding that the humanitarian situation has already been deteriorating years after an Israeli blockade on the coastal enclave.

Continuous population increase will constitute an additional burden on the agency, which cares for the refugees who make up nearly two thirds of the population.

Turner said that the UNRWA assessments indicate that the economy's growth will be slow "and this increases the humanitarian difficulties for the people."

The UNRWA provides food, education and health services to the refugees and is currently facing a budget deficit.