The head of the UN refugee agency on Thursday rejected as "offensive" a Guardian report alleging that the organisation was "starving" asylum-seekers in Libya. "I find that accusation offensive," UNHCR chief Filippo Grandi told reporters in Athens.

"I don't know where you read that report. Us, starving refugees and migrants in Libya? When my colleagues, day in, day out, risk their lives to access people that are often detained by criminal gangs?" he said.

The British daily earlier Thursday said it had seen a document circulated among UN staff saying that UNHCR would "phase out" food catering in a Tripoli centre under its supervision from 31 December.

"After that, the facility will no longer be used as a transit centre, the document said, until the remaining refugees and migrants 'vacate voluntarily'," the daily said. The Guardian said it had spoken to an aid worker who said "they're just trying to starve them to motivate them to leave" and that hundreds "have apparently been without food for weeks".