Huge cache of explosives found in Yemen after blast kills two al-Qaida

WASHINGTON -- Yemeni authorities last month recovered a huge cache of plastic explosives from the scene of an accidental blast that killed two al-Qaida operatives, confirming government fears of a serious ongoing terrorist threat in that region, U.S. intelligence sources said Tuesday.

Authorities discovered 650 pounds of Semtex secreted in a warehouse in the capital of Sanaa, where the Aug. 9 blast occurred. The Semtex was hidden in 13 crates covered by piles of pomegranates, the sources said.

The two men, identified in Yemeni news reports as Abd-al-Karim al-Jabiri and Abdallah Muhammad Fari, died when another explosive device, a wire-guided missile, blew up. Several others fled. Yemeni officials investigating the explosion found a stockpile of weapons, including rocket-propelled grenades and the Semtex, U.S. officials said.

An al-Qaida operative in custody in Afghanistan has separately told U.S. interrogators about a cell in Yemen that was preparing to use explosives against American targets there, according to a U.S. intelligence official. "He said these guys wanted to come get us," the official said.

The detainee did not know of the explosion and the recovery of the Semtex when he disclosed information about the Yemen cell, the official said.

For weeks, the U.S. government has expressed strong concern about the safety of Americans in Yemen. Though U.S. authorities are relieved to have taken a large amount of explosive material out of circulation, they are alarmed that the al-Qaida cell could possess that much and fear what it may portend elsewhere. They are also concerned that some cell members are still at large.

Semtex is manufactured in the Czech Republic and is similar to C4, a plastic explosive made by the U.S. military. While plastic explosives can be molded into different shapes, the Semtex recovered in Yemen is described as old and brittle, though still highly explosive.

"It is a wartime military explosive, by and large," said Chris Ronay, president of the Institute of Makers of Explosives. A quantity of 650 pounds, he said, "is pretty potent." That amount of material would equal about half the explosive power of the 1,400-pound urea nitrate bomb that was used in the 1993 attempt to bring down the World Trade Center.