Two women pleaded guilty Wednesday to conspiracy, arson and bomb charges in the 2001 firebombing of the University of Washington's horticulture center.

Jennifer Kolar, 33, and Lacey Phillabaum, 31, were released without bail after entering the pleas in U.S. District Court in Tacoma. Authorities said the two turned themselves in and have cooperated with ongoing investigations.

Under their plea agreements, prosecutors will ask U.S. District Judge Franklin Burgess to waive mandatory minimum sentences on the charges of arson, attempted arson and use of a destructive device. That bomb charge alone would otherwise carry a statutory minimum of 30 years, and a maximum term of life.

The fire on May 21, 2001, severely damaged the university building, which was rebuilt at a cost of about $7 million. The center had done work on fast-growing hybrid poplars in hopes of limiting the amount of natural forests that timber companies log.

The Earth Liberation Front, a shadowy collection of environmental activists, claimed responsibility and issued a statement saying the poplars pose "an ecological nightmare" for the diversity of native forests.

The plea deals instead will ask that Kolar serve five to seven years and Phillabaum face a recommended sentence of three to five years. Sentencing is scheduled for Jan. 5.

Neither woman commented to reporters after leaving the courtroom.

After the hearings, U.S. Attorney John McKay said the women had "the misguided belief that they would influence public policy. They have not."

"These violent acts of destruction are not a valid form of political speech," he said, calling the arson an act of domestic terrorism.

Kolar also pleaded guilty Wednesday to an attempted arson charge for a failed 1998 firebombing that damaged a Colorado gun club that organized a multistate turkey shoot.

Under the plea deal, the two women will not face additional prosecution for other attacks, including Phillabaum's admitted role in destroying five acres of canola in Eastern Washington state and Kolar's alleged part in arsons in Oregon in 1997 and California in 2001.

At least three others were involved in the UW firebombing, court documents allege.

Briana Waters of Berkeley, California, has pleaded not guilty and is scheduled for trial in May. William Rodgers of Prescott, Arizona, committed suicide in jail after being charged with other acts of ecoterrorism.

A fifth suspect, Justin Solondz, formerly of Jefferson County, Washington, remains at large.