Johnston has been held since 12 March

Hamas statement

A Hamas spokesman told the BBC that if Johnston was not freed, it would be the role of the Palestinian government to work for his safe release.

The reporter was abducted in March by a group calling itself The Army of Islam.

On Friday, Hamas said that Johnston should be freed and that it was in contact with his abductors.

"Alan Johnston was discussed with the kidnappers," Mahmoud Zahhar, the former Palestinian foreign minister who is believed to be a leader of Hamas, told the BBC Arabic Service.

They have been given a deadline of today, Monday, to respond

Mahmoud Zahhar, Hamas

Timeline: Johnston missing

"They have been given a deadline of today, Monday, to respond. They will be contacted, they may have already been contacted, for his release. If he is not released then the role of the current government is to work for his release, safe and sound."

In a separate interview with Reuters news agency, Mr Zahhar said: "If he is not released, we would use all means to secure his life and to free him."

Hamas, which seized control of Gaza last week and was ousted from the Palestinian government, has said reporters should be treated as guests.

The Army of Islam has threatened to kill the BBC man if certain Islamist prisoners - in particular Palestinian-born cleric Abu Qatada, who is detained in the UK - are not released.

Hamas leader Mahmoud Zahhar says negotiations are continuing

In a video released on Sunday, Johnston's captors denied they had reached a deal with Hamas for his imminent release but acknowledged that there had been "developments" in meetings with Hamas.

"There are developments and we will let you know when there are new developments," a masked spokesman said.

"If they do not meet these demands there will be no release of this prisoner, but if things get worse we will get closer to God by killing this journalist."

Johnston 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.

Several foreigners have been seized in Gaza in recent years and all have been released unharmed, but none has been held as long as the BBC reporter.