UN Secretary General Ban Ki-moon has repeated his call for the immediate release of missing BBC Gaza correspondent Alan Johnston.
Mr Johnston's image was projected on BBC Television Centre Monday
In London, a minute's silence was held at the UK's main radio awards ceremony, the Sony awards, to highlight the demand to free Mr Johnston.
BBC radio presenter John Humphrys, who received an award, paid tribute to him, saying Mr Johnston deserved it more.
Mr Johnston was seized at gunpoint in Gaza on 12 March.
Mr Ban also said he was hoping for Israeli-Palestinian moves that would lead to the release of the Israeli soldier, Gilad Shalit, who has been missing since being seized by Palestinian militants last year, and Palestinian prisoners.
Speaking to the UN General Assembly in New York, Mr Ban said: "I very much hope that we shall soon see the release of the Israeli soldier Gilad Shalit, accompanied by corresponding measures on the Israeli side. I also take this opportunity to plead for the immediate release of the BBC journalist Alan Johnston, abducted in Gaza. "
Receiving his award for news journalist of the year at the Sony awards ceremony in London, Mr Humphrys said he did not deserve the honour.
John Humphrys is a long-standing presenter of the Today programme
He said BBC correspondents who faced danger on a regular basis, above all Mr Johnston, deserved the award more.
Mr Humphrys named nearly a dozen BBC correspondents, calling them unsung heroes who faced danger week in and week out.
"Frankly if we weren't so obsessed with personalities and celebrities they're the people who should have had the award," he said to the applause of the audience at the Sony Radio Academy Awards.
"And I know we've mentioned his name before, but would you mind awfully just standing up and remembering Alan Johnston."
On Monday, European members of parliament said they were told by Palestinian leaders that Mr Johnston was alive.
There has been no direct information on the correspondent's fate since he was seized at gunpoint in Gaza City on 12 March after leaving his office.
On Monday evening, an image of Mr Johnston's face was projected on the outside wall of BBC Television Centre in west London.
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.