Speaking three years after the September 11, 2001, attacks against the World Trade Centre in New York and the Pentagon, outside Washington DC, Kazuhisa Ogawa warned that Japan will inevitably be on the wish-list of al-Qaida-linked groups.
"It is folly to imagine that these terrorists would not target Japan, which is after all the second largest economy in the world," said Ogawa, who has given Prime Minister Junichiro Koizumi one-on-one briefings on the threat posed to Japan.
"So far, Japan has not been directly associated with a terrorist attack, but that's simply a lucky coincidence."
Japan and its interests - from the skyscrapers in the heart of Tokyo's business district to the seat of government and corporations that are known around the world - are likely to be a target because Koizumi has been a staunch supporter of US President George W Bush's "war on terror" and authorised the dispatch of members of the Self-Defence Forces to Iraq.
That controversial action - the first time Japanese troops have served in a war zone overseas since the end of World War II - has prompted some clear threats.
Up until now security has never
been a top government priority
Shortly after the decision to send the SDF to the southern city of Samawah, the London-based al-Quds al-Arabi newspaper quoted a message from an al Qaida-affiliated group, Brigades of the Martyr Abu Hafz al-Masri.
"We tell the criminal Bush and his Arab and non-Arab followers, especially Britain, Italy, Australia, and Japan, that cars of death will not stop at Baghdad, Riyadh, Istanbul, Jerba, Nasiriyah or Jakarta," it said, referring to car bombings.
"The reason Japan has not yet been attacked is that it is much easier for undamentalists to do a bombing in Spain, for example, than focus on an island far away and because Japan is very homogenous and people with Arabic or Western features find it more difficult to be active in Japan," he said.
But that may have lulled Japanese society into a false sense of security.
"Talking about the state of crisis management in Japan today, I have to say that these concepts and the understanding of the problem is very low," he said.
And it is not as if Japan has not had a warning, he said. The entire country was shocked - and authorities were left red-faced - when police in Germany arrested Lionel Dumont, 34, in connection with an investigation into al-Qaida.
Dumont had been working as a used-car dealer in the city of Niigata between July 2002 and September 2003 while allegedly laundering al-Qaida's money. Dumont was arrested before boarding a plane at a Germany airport in December.
Japanese police were acutely embarrassed by the revelations that Dumont, who is of Algerian descent, was living in Japan on a forged passport that identified him as Tinet Gerald Camille Armand.
His arrest sparked a wide-ranging police investigation that led to the arrest of eight more people who had one business with him, including a Malian, a Pakistani, and a Bangladeshi national.
With around 200,000 Muslim immigrants living across Japan, the concern is that some of them may harbour jihadist beliefs and be ready to take a more active role in opposing a government that supports the United States in its Middle East policies.
With that in mind, security has been stepped up at key points in Tokyo, including the embassies of Western nations, the Imperial Palace, the national Diet building, and ministries in the Nagata-cho district.
New signs on the subway system warn that closed-circuit television cameras have been installed and that unattended packages or people who are acting suspiciously should be reported to staff.
Crash barriers have been placed
outside Tokyo's Imperial Palace
Similar precautions are also being taken at facilities used by both the Japanese military and US forces based in Japan.
But Ogawa emphasises that al-Qaida does not even need to be in the country to wreak havoc on its infrastructure.
Other countries are investing a great deal of time and money in network security, improving both the cyber security of critical computer networks and the physical security of the facilities they rely upon to operate, such as power stations.
"The government in Japan still does not understand that security is not just an option that they can choose to have or not; it's a cost that must be borne"
Japanese military analyst
But Japan is 20 years behind the US and 10 years behind South Korea when it comes to the security of its computer systems, he believes.
"The field of technology moves forward very rapidly and the longer Japan waits, the worse the situation will get," he said.
"The government in Japan still does not understand that security is not just an option that they can choose to have or not; it's a cost that must be borne."
Experts fear that a concerted attack by hackers - even in another country - against the systems that the government uses in the event of an emergency, coupled with a physical attack on Japanese soil, could paralyse any attempted response.
"We need to take measures to combat the threat of terrorism," Ogawa says.
Modern, wealthy Japan may need
to take security threats seriously
"To avoid becoming a target, Japan needs to do two things simultaneously: it must upgrade its anti-terrorism policies, activities and abilities to a world-class level; and second, it must identify the countries and areas in which terrorists move freely and then work with other countries to stablise those regions.
"That is the reason why Japan is helping to reconstruct Iraq now," he said. "The situation in Iraq is dangerous but we cannot just abandon the reconstruction effort because if we don't help there now, Iraq could descend into anarchy, which provides the foundation for terrorist organisations to become active and in turn leads to danger for Japan."
And because only professionals who know how to defend themselves can be sent to Iraq until the country is safe for civilian construction firms to begin work, Japan's Self-Defence Forces will be needed there, he added.
"I feel very strongly that we must continue to be in Iraq and that we must continue to help with the reconstruction," Ogawa said.
"I don't think it matters if you were for or against the war, given the possible ramifications today, it is something that we have to do."
"I feel very strongly
that we must continue to be in Iraq and that we must continue to help with the reconstruction"
Japanese military analyst
But can the danger to Japan ever be truly eliminated?
"Al-Qaida members are religious fundamentalists and what they are trying to do is to create their idea of an ideal world based on their interpretation of the Muslim holy book," he said.
"The kind of society that they consider to be their greatest enemy are those that are modern and wealthy."