The kidnapping of foreigners has become a boom industry in Iraq, fuelled by an array of militant groups opposed to coalition forces and the US-backed interim government.
By Matthew Davis
BBC News Online
There has been evidence of the effects a hostage crisis has on public opinion
Clusters of extremist Islamist rebels inspired by al-Qaeda are, say experts, using kidnapping as an emotionally charged lever to pressure foreign governments, extort funds and win cheap publicity.
At the same time there has been an explosion in the abduction of ordinary Iraqis.
Those involved in negotiations with the hostage-takers have told BBC News Online they fear a dramatic rise in kidnappings if countries do not stand firm against demands for concessions.
And there are also concerns that foreigners taken by local criminal gangs are increasingly being "sold up the chain" to become pawns for the militant cells.
'Honey pot of targets'
Terrorism expert Professor Paul Wilkinson, of St Andrew's University, said hostage-taking was an increasingly important weapon for militant groups in Iraq.
"Iraq provided them with a honey pot of coalition targets. It gave them an opportunity to use kidnapping as a tactic and whetted their appetite for methods that reach over the heads of government to public opinion," he said.
"They may be operating with a combination of foreigners and local rebels, but they are part of the extremist Islamic movement, inspired by al-Qaeda which sees Iraq as a 'good opportunity'."
There are a range of groups at work.
The group of masked men who appeared in an internet video, apparently shooting a Turkish truck driver, stood in front of a banner resembling that of al-Tawhid and Jihad - a militant group reportedly run by Abu Musab al-Zarqawi, the Jordanian accused of a series of attacks in Iraq.
The al-Tawhid and Jihad group is also believed to have carried out the beheadings of two other hostages in Iraq - American Nick Berg and South Korean Kim Sun-il.
Militants who captured Filipino Angelo de la Cruz - the now-freed Filipino hostage - appeared under a banner saying Islamic Army, Khaled bin al-Waleed corps.
Other groups identified in recent months include the Green Brigade - which said it abducted four Italians, one of whom was killed; Islamic Response, Ansar al-Sunna and the Black Banners.
'Climate of fear'
Tallies by news agencies suggest that some 100 foreigners have been taken hostage in Iraq in recent months, with several high-profile killings.
There has been clear evidence of the effects a hostage crisis can have on public opinion in places such as Japan, South Korea, Italy, the US and the Philippines.
Zarqawi: Accused of heading the al-Tawhid and Jihad group
And the hostage-taking and threats which have dissuaded some companies from coming to Iraq, or seen firms or governments withdraw personnel, can be seen as a "success" for militants.
Responding to intense domestic pressure, the Philippines complied with the demands of the kidnappers of Angelo de la Cruz and withdrew their 51-strong force from Iraq a month earlier than planned.
Cairo refused to bow to kidnappers who seized an Egyptian diplomat, Mohamed Mamdouh Qutb, who was freed unharmed by his kidnappers on 26 July.
Canon Andrew White, head of the Iraqi Center for Dialogue, Reconciliation and Peace - a group working to free foreign hostages - said one of the keys to reducing the "circle of hostage-taking" was not to give in to demands.
"There is nothing straightforward about hostage negotiations. We don't know whether we are getting the truth," Canon White told BBC News Online.
"We sometimes have no contact for months. We have nine cases hanging over from April, new ones are coming to us all the time."
"The dangerous thing is that kidnappers are beginning to see demands being met, and this will only encourage more groups to take hostages."
'Muslim hostages freed'
Canon White's group works with a network of religious and tribal leaders who may act as intermediaries in negotiations.
But the vast majority of hostages taken in Iraq are Iraqis, not foreigners. One prominent example is Raad Adnan Mahmoud, the director of a state-owned construction company kidnapped in Baghdad on 24 July.
Dr Mustafa Alani, of the Dubai-based Gulf Research Centre (GRC), said ordinary citizens were being abducted at the rate of 10 per day.
Canon White says: "Ordinary Iraqi people are really frightened - it affects them most of all.
"People who are being particularly targeted are the children of the middle classes, and professional men - university professors, doctors.
"Most of the hostage-takers are small-time bandits trying to get quick cash.
"But a common trait we are seeing is that foreigners are being sold up the chain - from the small time criminals to the big, bad groups."
In some cases, efforts to free hostages can stand or fall on the background of the hostage.
Time magazine reports that of 35 foreign hostages freed in Iraq, 19 were either Muslims or came from predominantly Muslim countries.
And kidnappers who freed Mohamed Mamdouh Qutb said they had done so "because of the religious faith and moral qualities he possesses".