Vatican City - Pope Benedict XVI on Wednesday in a meeting with the head of a United Nations relief agency expressed concern over the plight of refugees attempting to flee the violence in Libya..

In a private audience at the Vatican, Benedict received World Food Programme Executive Director Josette Sheeran who earlier this week visited refugee camps along Tunisia's border with Libya.

"I was so moved that His Holiness asked for this briefing and expressed his concern for the innocent people trapped in this terrible tragedy," Sheeran said after the meeting.

In what the WFP described in a statement as being part of an "emerging humanitarian crisis," Sheeran witnessed an influx of "more than 2,000 people an hour" pouring into Tunisia from Libya.

Sheeran thanked the pontiff for the support given to the Rome-based WFP by Catholic relief institutions that often work together with the UN agency in distributing food during emergencies.

"The world must act - and must act quickly - to prevent a major humanitarian disaster," Sheeran said referring to the exodus of refugees from Libya.

On Monday a WFP flight left Italy for Tunisia, carrying a plane load of high energy biscuits to be distributed to the refugees.