With the clock ticking as the deadline approaches before kidnappers threatened to burn alive Noriaki Imai, 18; Soichiro Koriyama, 32; Nahoko Tokato, 34, their families spoke to Aljazeera television on Saturday.
Kidnappers are demanding Japan withdraws its 550 ground troops from Iraq. Tokyo vowed not to bow to the call.
"When my son went to Iraq, he made his best effort to show the suffering of the Iraqi people and volunteered to help needy children in hospitals," said Imai’s mother, Naoko.
Imai graduated from high school last month. He is a member of the Campaign to Abolish Depleted Uranium and travelled to Iraq on 1 April to study the effects of depleted uranium on Iraqi children. He was planning to write a book documenting the stories of victims of depleted uranium.
"I believe the Iraqi people will help us. My son has been busy with observing the Iraqis' suffering since the Gulf war. He even intended to publish a book on this issue," his mother told Aljazeera’s Tokyo correspondent Fadi Salameh.
"Noriaki has opposed war on Iraq. He has suffered a lot as he believes Iraqis need humanitarian help. Please free him as soon as possible."
Takato, 34, is also an aid worker and peace activist. She travelled to Iraq in April 2003, after US and British tanks entered Baghdad.
This was Takato's third trip to Iraq
"Nahoko went to Iraq a year ago in order to help the Iraqi children in hospitals and schools. She liked to play with Iraqi children to emotionally support them. She used to email us talking about the suffering of the Iraqis. She even wanted to contact the Japanese Prime Minister Junichiro Koizumi to tell him about what really happens in Iraq," her sister Aiako Inoue told Aljazeera.
Koriyama is a former soldier turned freelance photojournalist. Last May, Koriyami provided the Weekly Asahi magazine, published by the mass-circulation Asahi Shimbun, with pictures of Baghdad after the city fell.
"He has opposed war on Iraq and done his best to help families of harmed Iraqis, particularly children. He has tried to show their suffering to the whole world," said his mother, Kimiko.
"I call on all Iraqis to help the three Japanese hostages who have gone to Iraq only to help Iraqi children. Please save them."
Meanwhile, Japan issued a videotaped demand on Saturday for the release of the hostages.
"To the members of Saraya al-Mujahidin, who have taken
three Japanese hostage," Foreign Minister Yoriko Kawaguchi said in the footage, which was to be distributed to TV broadcasters around the world on Saturday, including an Arabic version.
"The people of Japan and I strongly demand an immediate and
safe release of the three hostages."