There is growing uncertainty about the fate of three Japanese citizens taken hostage last week in Iraq.
Hostages' families deliver a petition calling on the government to act
Japan is still waiting for news of the three, more than 24 hours after reports surfaced that their Iraqi captors would free them.
But reports that their release was imminent proved unfounded, and it was no longer clear whether they were safe.
The kidnappers had threatened to kill them unless Japan withdrew its troops from Iraq - a move rejected by Tokyo.
The government had been told that the three were still being held by militants near the flashpoint town of Falluja, west of Baghdad, Kyodo news agency reported.
Arabic al-Jazeera TV reported on Saturday evening that the captors decided to release them after an appeal by Muslim clerics, but no more has been heard since.
Meanwhile the official Chinese news agency says seven Chinese civilians are reported to have been abducted, probably in Falluja. The Beijing government later confirmed the report and called for their immediate release.
The seven men, all from the eastern province of Fujian, are said to have been abducted by an armed gang early on Sunday, after crossing into the country from Jordan.
The BBC's Rupert Wingfield-Hayes says the kidnappings could have been timed to coincide with US Vice-President Dick Cheney's visit to Beijing.
Elsewhere, the Arab television network, al-Jazeera, has shown pictures of masked gunmen with another eight captives, apparently from several Asian countries. They are thought to have now been released after pledging not to cooperate with the coalition.
'Help my son'
With little news emerging, the distraught relatives have made further pleas to the Japanese government to act to save them.
"What we want most of all is for the troops to be withdrawn to save their lives," Ayako Inoue, sister of aid worker Nahoko Takato told Reuters.
Ms Takato, 34, is being held together with Noriaki Imai, 18, who was in Iraq to research the effects of depleted uranium weapons and 32-year-old photojournalist Soichiro Koriyama.
People in Tokyo react to the hostage crisis
"We thought we would see the cheerful face of my son by noon, but we have not received any confirmation yet," Mr Koriyama's mother Kimiko said, a reference to reports that the hostages would be freed by Sunday lunchtime, Japanese time.
"Please help my son."
But Chief Cabinet Secretary Yasuo Fukuda said there was no longer any certainty of a favourable end to the crisis.
"At one point we were able to make the judgment from
various perspectives that they were safe, but now that's
unconfirmed," he said.
'Image at stake'
Video footage last Thursday showing the three hostages blindfolded, and with a gun to their heads, stunned the Japanese people.
Correspondents say that in safe and orderly Japan the kidnappings have been a source of nationwide anguish.
On Sunday, several hundred people demonstrated in Tokyo, Osaka and Akita to call for the hostages' safe return and the withdrawal of Japanese forces.
JAPAN'S IRAQ MISSION
550 troops in Samawah
Helping to rebuild infrastructure
First time pacifist Japan has sent troops to combat zone
The Japanese public is sharply divided over the sending of 550 troops to Samawah in southern Iraq. Critics argue it violates the country's pacifist constitution, especially if the troops are drawn into violence.
That possibility was underscored on Thursday, when mortars exploded near the troops' base.
But Mr Koizumi would jeopardise Japan's international standing if he pulled out, analysts say.
Mr Cheney, who is on a visit to Japan, is expected to urge Mr Koizumi to stay the course in Iraq when he meets him on Monday.