The provocations have been so severe over such a long period of time now that the general reasoning in the U.S. at this time is that some kind of attack using "poor man" weapons of mass destruction has become not a matter of "if" but "when". The subway system remains especially vulnerable; as do public theaters and museums where only visual rather than actual security checks are now in place in most cases.

KFAR SABA, Israel (AP - 22 April) - A suicide bomber detonated his explosives at a crowded bus stop in a Tel Aviv suburb Sunday, killing himself and one Israeli, and injuring 39 others, police said.

The attacker, believed to be a Palestinian, set off the bomb as the bus stopped to pick up passengers along a busy street in the middle-class suburb of Kfar Saba, police said.

``When the bus arrived, a suicide bomber approached it and leaned against it while setting off a device,'' said Yehuda Bahar, a police commander in the region.

Israel has been rocked by repeated explosions carried out by Palestinian militants since the Palestinian uprising began seven months ago. Prime Minister Ariel Sharon has pledged swift and harsh retaliation for such attacks, and Israel has carried out several raids following mortar attacks by Palestinians.

No one immediately claimed responsibility for Sunday's attack.

Police said the bomber and an Israeli were killed in the explosion that went off about 9 a.m. as commuters were heading to work Sunday, the beginning of the work week in Israel.

Ambulances and rescue workers rushed to the scene, and police sealed off the area and searched for additional explosives.

Thirty-nine people were injured, including a child who was seriously hurt, police and rescue workers said. Most of the injured were moderately or lightly wounded and the total included some suffering from shock, officials said.

``I heard a large blast,'' witness Gil Levy told army radio. ``I approached the area and I saw a lot of people lying on the ground and I saw people screaming. I saw one man totally blown apart.''

Two bombs went off last week in Kfar Saba, but no one was killed. The suburb is northeast of Tel Aviv, only a few miles from the Palestinian-controlled city of Kalkilya, in the West Bank. Israel had stepped up security in the area following the recent bombings.

Meanwhile, a member of Palestinian security forces, injured last Monday in an Israeli raid, has died of his wounds, a Palestinian hospital official said. Madhi Khalil Madhi, 35, was badly hurt when an artillery shell hit the security compound where he was working.

Sunday's bomb blast followed a U.S.-sponsored meeting between Israeli and Palestinian security chiefs on Saturday night. After four hours of talks, Israel agreed to ease some punitive measures against the Palestinians on Sunday, the army said.

Sharon's office said the sides agreed in the talks to resume limited security cooperation, which broke down during the months of fighting. The Palestinians said the two sides also discussed the possibility of resuming the peace process.

``This was not only a security meeting but also a political one with the idea that political negotiations would make our work much easier,'' said Abdel Razek Majaidah, a senior Palestinian security official and a participant in the talks.

Israel's Foreign Minister Shimon Peres said Israel was willing to hold talks as part of its determined efforts to stop the bloodshed that has killed 478 people.

``Violence cannot be stopped only by the use of force. It's also necessary to talk,'' said Peres, an architect of the first Palestinian accord with the Palestinians in 1993.

However, given the hostile climate and the ongoing violence, no breakthroughs were expected on the peace front.

Israeli Cabinet Minister Danny Naveh insisted Sunday that all talks with the Palestinians were aimed at ending the current hostilities, not resuming the peace negotiations. Sharon has repeatedly said he will not negotiate ``under fire.''

According to Israel radio, the Palestinians agreed to work to stop the shooting from the areas they control. In addition, the Palestinians have arrested several members of the radical Hamas movement in recent days, the radio said.

Majaidah, the Palestinian official, said the atmosphere at the meeting was tense and Israel's commitment to ease some restrictions on Palestinians was ``insufficient.''

Even as the talks were taking place Saturday night, violence persisted. A mortar shell was fired toward the isolated Jewish settlement of Netzarim in the Gaza Strip, the army said. The shell fell short, landing in a Palestinian area, and no injuries were reported.

To date, 478 people have been killed in the fighting, including 394 Palestinians, 65 Israeli Jews, and 19 others.

[The Independent - 22 April 2001]: The US government has ordered 40 million doses of smallpox vaccine from a British company in a sign of the growing alarm that terrorists could unleash lethal viruses in future battles against Western states.

The astonishing size of the contract ­ worth $343m (£200m) ­ highlights the fears on both sides of the Atlantic about the threat of biological terrorism. If a virus such as smallpox was released, the speed of modern communications could spread the infection all over the world in days.

In the UK, the health department warned all NHS hospitals last year to prepare for a criminal or terrorist attack on their local populations involving biological weapons. Police teams trained by scientists from Porton Down, the government research centre on biological and chemical warfare, have been formed to take the lead role in the event of an attack.

The British Medical Association said that advances in technology meant biological weapons were now easier to manufacture than chemical ones, increasing the risk that they could be used in an attack.

Over the past 40 years there have been 121 incidents around the world involving the use of biological agents. The use of sarin nerve gas in an attack by a Japanese terrorist organisation six years ago, in which 12 people were killed and 5,000 injured, focused world attention on the threat. The US last year set aside $1.4bn (£940m) for protection against chemical or biological attacks.

The latest contract for smallpox vaccine is against a disease that no longer exists ­ and the world must hope it will never encounter again. It was eradicated from the planet in 1980 and only two research institutions ­ one in the US and one in Russia ­ still retain stocks of the virus.

The threat of a smallpox attack is highlighted in the preview edition of Infectious Diseases, a new journal published by The Lancet. Donald Henderson of the Johns Hopkins School of Public Health said: "A large stockpile of vaccine is a very high priority because smallpox has a 30 per cent fatality rate. There is no vaccine production capacity anywhere in the world and we now have a very susceptible population."

The vaccine ordered by the US government is being manufactured by a US subsidiary of the Cambridge-based UK biotechnology company Acambis, formerly known as Peptide Therapeutics. Delivery to the US government's Center for Disease Control in Atlanta is due to start from mid-2004.

A spokeswoman said: "At the moment we are going through the process of developing and licensing the vaccine, but under the contract we have the right to sell it to anyone who wants it. When the time comes we will be marketing it to other governments, including the UK. It certainly would be a logical step for them to take."

The likelihood of a chemical or biological attack in the UK is seen as low by the Department of Health, but the results could be devastating. Working parties have been set up to consider the threat and exercises have been run in parts of the country. Lists of the most likely agents to be used have been drawn up, together with advice on how many people they might kill or injure, and strategies for treating the victims.

In the US, fear of biological terrorism has become as unnerving as the threat itself. President Clinton's declaration in 1998 that he expected a biological or chemical attack within the next five years has fuelled alarm and provided fertile ground for hoaxers.