The health ministry has instructed local authorities to tighten security at waterworks and reservoirs to prevent terrorist attacks involving lethal bacteria being used to infect water sources, the ministry said Friday.

The Health, Labor and Welfare Ministry also requested that prefectural and municipal governments step up inspections of foodstuffs in storage and during distribution, a move apparently triggered by last month's terrorist attacks on New York and Washington.

The ministry requested in a notice that local authorities step up measures to safeguard the quality of water at water facilities and reservoirs. It also called for improved security at such sites, including more stringent checks of visitors' identification.

The ministry called on authorities to stop pumping water from facilities in the event of a terrorist attack using biological agents.

In a similar move, local authorities were asked to step up inspections of foodstuffs to prevent terrorists from contaminating them with dangerous bacteria during storage and distribution.

Experts say terrorists would most likely use plague bacillus, variola virus or arsenic in such attacks.

The ministry asked authorities to establish a system to prevent the spread of infection in the event that a bioterrorist attack causes casualties.

It also requested the creation of a system to promptly provide victims with first aid following an attack.

The ministry called on the authorities to draw up plans to prepare for an attack, including strengthening inspections and confirming the presence of bacteria, as well as promoting studies on the causes of sicknesses that medical facilities are not familiar with.

The ministry also ordered that communications with police and firefighters be double-checked.

"We cannot rule out the possibility that Japan may become a target for terrorists, because it plans to extend assistance to the U.S.-led retaliation (against the Sept. 11 attacks)," a ministry official said.