Rome, Sep 29 (IANS/AKI): Barriers like razor-wire erected by Hungary on its border with Serbia in a bid to keep out migrants are not sustainable, Pope Francis has said.

"You know how walls finish up," Francis said. "All walls collapse -- today, tomorrow or after 100 years. Walls are not the solution. The problem remains, but with more hate."

Hungary, which has registered more than 220,000 asylum-seekers this year amid Europe's biggest migration crisis since World War II, is building a four-metre high fence along its 175 kms border with Serbia and barriers on parts of its border with Croatia and Romania, drawing sharp criticism from the EU.

During his five-day visit to the US last week, Francis urged a humane response to migration, both from Central America and war-wracked countries such as Syria.

"We must not be taken aback by their numbers, but rather view them as persons, seeing their faces and listening to their stories, trying to respond as best we can to their situation," he told the US Congress.

"Let us treat others with the same passion and compassion with which we want to be treated,'" Francis said.