Two Bulgarians are the latest workers in Iraq facing a threat to their lives after being kidnapped yesterday.
Militants have also threatened to behead a kidnapped Filipino if Manila fails to withdraw workers supporting coalition forces in the country.
Bulgaria, which has contributed 470 troops to the multinational force, says it will not bow to the demands kidnappers holding civilian truck drivers Mr Ivailo Kepov and Mr Georgi Lazov.
The Prime Minister of Bulgaria, Mr Simeon Saxe-Coburg said today that his government will do all it can to save two hostages. However, when asked if the authorities would negotiate with the captors,
who have threatened to kill the two men, he told reporters on a visit to Belgrade that Bulgaria would act in a responsible way.
He said it was necessary in such situations to "engage all possible channels, means and connections. We will make all our efforts to help and save our citizens."
Earlier, the Bulgarian Foreign Minister, Mr Solomon Passy said that: "Bulgaria is a stable state with a predictable foreign policy and we cannot expect it would change its foreign policy because of one or another group."
Al Jazeera television showed a tape from Jordanian militant Abu Musab al-Zarqawi Tawhid and Jihad group in which the two Bulgarians were seen sitting in front of masked and armed captors. The men would be decapitated in 24 hours if the United States did not release prisoners from the group, a speaker on the tape said.
The al-Zarqawi group, which has strong links to al-Qaeda, has already beheaded an American and a South Korean in Iraq. Iraqi Prime Minister Allawi views al-Zarqawi as a deadly threat and this week provided the US with the intelligence which led to an air strike on Monday targeting his network in the western city of Falluja.
The family of Filipino driver Mr Angelo de la Cruz appealed to the Manila government to bring him home as diplomats tried to contact the militants threatening to decapitate him.
Gunmen holding Mr de la Cruz said on Wednesday they would kill him unless the Philippines, a staunch US ally, pulls its force of about 50 humanitarian workers out of Iraq within 72 hours.
At least four hostages have been killed. Yesterday, Lebanese-born US Marine Wassef Ali Hassoun, reported at one stage to have been beheaded by militants after going missing in Iraq, was confirmed to be safe at the US embassy in Beirut.
In another twist, relatives of Marine Hassoun fought a gunbattle with a family who taunted them as US agents in the northern Lebanese city of Tripoli, witnesses said.
At least two people were killed.