Militants threatening to kill three U.N. hostages pushed back their deadline until Wednesday evening, saying negotiations were continuing on demands that include the world body's withdrawal from Afghanistan.

Afghan officials and colleagues of the three foreign election workers expressed hope that the abduction will eventually end with their safe release.

There was no confirmation that the kidnappers had been contacted or the victims located. Still, an official said Wednesday that police units had launched a fresh search operation west of Kabul.

A Taliban (search) splinter group claims it abducted Annetta Flanigan of Northern Ireland, Filipino diplomat Angelito Nayan and Shqipe Habibi of Kosovo in the Afghan capital last Thursday.

Jaish-al Muslimeen, or Army of Muslims, released a videotape on Sunday showing the frightened captives pleading for their freedom. However, several Afghan officials say they suspect that warlords or criminal groups were also involved in the bold daylight snatch.

Syed Khaled, a purported spokesman for the group, told The Associated Press on Wednesday that talks with government and U.N. envoys were taking place at an undisclosed location.

"We will decide this evening what we will do," Khaled said in a satellite telephone call.

He declined to say whether that meant the hostages could be killed or if a new deadline would be set.

U.N. spokesman Manoel de Almeida e Silva refused to discuss any negotiations, saying it could endanger efforts to free the hostages. The Philippine government, which has sent diplomats to Kabul to seek their freedom, also imposed a news blackout.

Still, one election official said privately that there was some optimism that the three would be released. "We have a good feeling," the official said.

Latfullah Mashal, a spokesman for the Interior Ministry, which is leading Afghan government efforts to find the hostages, said the ministry had "not been informed" of any contacts with the kidnappers.

But he said the ministry, whose security forces are leading the search, had undertaken unspecified initiatives which were "going well."

"We're progressing and hopeful that the hostages will be released safely," Mashal said.

He declined to elaborate. But another government official, speaking on condition of anonymity, said police units had been deployed to Wardak, a province west of Kabul, on Tuesday evening.

"They're searching there in two or three places," the official said.

Afghan security forces, backed up by NATO troops based in Kabul, have also focused their search in the city and the neighboring Paghman valley.

The militants say that they have divided up the hostages to thwart any rescue attempt, and warned authorities to back off.

All three hostages were in Afghanistan to help manage its Oct. 9 presidential election.

U.S.-backed interim leader Hamid Karzai (search), who has condemned the latest kidnapping, secured a majority of the votes, but is still awaiting official confirmation as the country's first popularly chosen leader.