Letters rigged to ignite when opened and bound for the governor's offices in Virginia and West Virginia were intercepted Monday, officials said. Governor's offices in at least 16 other states got similar letters last week.

The letter that arrived in Richmond never threatened Gov. Mark R. Warner (search), said Bill Leighty, the governor's chief of staff. The letter, addressed to "executive chambers" in the state Capitol, was uncovered at a central postage-handling facility, Leighty said.

A letter to Gov. Bob Wise (search) of West Virginia was intercepted there.

Like the letters received last week, both bore a return address from Nevada's maximum-security Ely State Prison (search).

"It's a sad reminder that we live in a dangerous world," Warner said during a break in the Southern Governors Association (search) conference, being held in Richmond.

At least three of the 16 letters received last week caught fire, but no one was hurt.

Authorities said they were interviewing inmates at the prison.

The letters listed one or the other of two Ely inmates as the sender, but authorities are not sure if either prisoner was involved, Glen Whorton, assistant director for the Nevada Corrections Department, said last week.

"We're not assuming the names on the envelopes are simply the end of the matter," he said. "Investigators are not just talking to the two inmates."

Letters were sent to governors' offices last week in Alaska, Arizona, Colorado, Hawaii, Idaho, Massachusetts, Montana, Nebraska, Nevada, New York, Oregon, Texas, Utah, Vermont, Washington and Wyoming. In addition to the governors, Nevada's corrections director received a booby-trapped letter.

The Montana Capitol was partly evacuated Thursday when the match burned the letter opened there, but there was no further damage.

All mail bound for Virginia's executive offices on the third floor of the state Capitol is routed through an off-site receiving facility to protect the governor and his staff. "We've done it for this very reason," Leighty said.