The Palestinian Islamist movement, Hamas, says it is taking "practical steps" to secure the release of kidnapped BBC reporter Alan Johnston.
Alan Johnston was abducted at gunpoint in Gaza on 12 March
Hamas said it had sent a warning to Mr Johnston's kidnappers, hours after the movement claimed victory in a bloody power struggle in Gaza.
A spokesman said Mr Johnston, a hostage for three months, was the Palestinians' guest and should be made welcome.
The reporter was abducted in March by a group calling itself The Army of Islam.
Palestinian militants purportedly belonging to the group posted a video on the internet on 1 June showing the first pictures of the reporter, in which he said he was being well treated.
The 45-year-old was the only Western reporter permanently based in Gaza and his abduction has triggered appeals for his release from lawmakers and rights groups around the world.
More than 160,000 people have now signed an online petition calling for his release.
Hamas spokesman Abu Obayda said his organisation would no longer allow the journalist to be held captive and that it was in contact with Mr Johnston's abductors.
"We have sent a message to his kidnappers to release him immediately. We warned against not setting him free. This is all I can say now," Mr Obayda told a news conference.
He said the group "will not allow anyone to attack journalists or foreigners, because they are helping our people".
Mr Obayda was speaking a day after Hamas seized control of Gaza after a week of fierce fighting with Palestinian Authority President Mahmoud Abbas' Fatah forces.
In response Mr Abbas has dissolved the three-month-old unity government and appointed a new prime minister.
He says he plans to rule by presidential decree until conditions are right for elections.