Yet, as I write, the attacks by extremists with sophisticated explosives upon scientists, whom their more moderate critics agree are decent people, continue.

American intelligence officials have centered their attention on Middle Eastern groups that have a history of using sophisticated explosives that may have caused the downing.

In Mindanao, though, the training appears to include more of a special emphasis on the use of sophisticated explosives, the officials said.

"We have seized rockets, mortars, machine guns, a great quantity of sophisticated explosives and radio equipment," the general said.

The use of such a sophisticated explosive would heighten suspicions of a carefully orchestrated or possibly state-sponsored terrorist plot.

Coalition forces have other material advantages: American and British infantry will use sophisticated wall-breaching explosives to enter some buildings without using doors and windows.

The Quds Force is under intense scrutiny by American intelligence agencies because it is suspected of supplying sophisticated explosives to Iraqi militants.

The cargo - rockets, antitank grenades, sophisticated explosives - was impressive.

Recruits were drilled in the manufacture and use of sophisticated explosives, as well as in the Koran.

What scared them, they said, were the roadside bombs and other, more sophisticated explosives that Palestinians had been using lately, like mortars and this morning's antitank grenade.