The United Nations Commissioner for Human Rights, Louise Arbour, has made an appeal for the release of BBC Gaza correspondent Alan Johnston.
Mr Johnston was the only Western reporter based permanently in Gaza
The 44-year-old journalist has not been seen since he was seized at gunpoint on his way home in Gaza City on 12 March.
Speaking in Geneva, Ms Arbour said she was extremely distressed by Mr Johnston's abduction.
Earlier, special vigils were held in London and Paris, marking the start of his ninth week in captivity.
Ms Arbour, who met Mr Johnston last year, called for international solidarity to protect the freedom of the press.
"I certainly share in the sentiments of his family and his friends and I join in their appeal to those who are holding him to release this very decent man," she said.
Since Mr Johnston's abduction no public demands have been made or information released on his whereabouts.
And there is still no clear information about what state of physical or mental health he may be in.
The Palestinian Authority, the BBC and the UK government say that they are working as hard as possible to secure his release.
His abduction has severely limited reporting of a key part of the Middle East story, BBC Middle East correspondent Tim Franks says, much to the frustration of Palestinians in Gaza.
Mr Johnston joined the BBC World Service in 1991 and has spent eight of the last 16 years as a correspondent, including periods in Uzbekistan and Afghanistan.
He has lived and worked in Gaza for three years and was the only Western reporter permanently based in the often violent and lawless territory.