US ally Romania has not responded to the abductors despite opposition party calls to consider a partial withdrawal of troops, and the Tuesday 1400 GMT deadline expired amid street protests for the release of the reporters.
Prima TV news director Dan Dumitru said on Tuesday that his station had received a call from the kidnappers and the hostages - Prima TV reporter Marie Jeanne Ion, 32, cameraman Sorin Miscoci, 30, and Romania Libera daily journalist Ovidiu Ohanesian, 37.
"About three hours ago I received a call from Iraq ... our colleagues want us to put pressure on the government to take a decision [on the troops]," Dumitru said.
Sources at the station said the abductors gave Romania a further 24 hours to respond to their demands.
In a video tape aired by Aljazeera on Tuesday, the three journalists, seized in Baghdad on 28 March while on a short reporting trip, were shown sitting on the floor and handcuffed.
Aljazeera said the three made a "final appeal" to Romanian President Traian Basescu to heed the kidnappers' demands, adding that the kidnappers had set 1400 GMT on Wednesday as the deadline for killing them if the demands were not met.
A separate tape showed their translator Muhammad Munaf, who has US, Romanian and Iraqi citizenship, asking US President George Bush to help save his life.
Miscoci was shown wearing orange overalls, and Romanian TV commentators described this as "the colour of death", saying Iraqi fighters had dressed hostages in this colour in the past to show their death threats were serious.
The new centrist Romanian government has not said whether it will pull out the 800 troops sent to Iraq when the former communist PSD party was in power. The PSD called on Monday for a gradual pullout but not under pressure.
Government officials declined to comment.
A Romanian pullout would be a further blow to US efforts to persuade as many allies as possible to contribute troops to Iraq.
Italy, Bulgaria, Poland and Ukraine are looking at reducing their presence there.
"This is the hardest day, we are thinking that their hours are numbered"
Elena, mother of hostage cameraman Sorin Miscoci
An opinion poll on Sunday showed 70% of Romanians think the new Nato member should withdraw its soldiers from Iraq to save the journalists' lives.
"This is the hardest day, we are thinking that their hours are numbered," said Miscoci's mother Elena at a gathering of hundreds of protesters in central Bucharest. "We trust the authorities until the end."
Other relatives of the kidnapped journalists joined the protest and appealed to Basescu to pull out the troops.
US soldiers killed
The US military, meanwhile, reported that an American soldier was killed in Iraq in a vehicle accident on Tuesday north of capital Baghdad.
Another soldier was killed on Saturday by a roadside bomb that struck his convoy near Haswah, west of Baghdad, the military said.