SEATTLE - From excessive strip searches and overcrowding to a lack of due process, an immigrant advocacy group alleges detainees are being mistreated at the Northwest Detention Center in Tacoma, which houses illegal aliens in the process of deportation.

The study - released by Seattle-based OneAmerica and the International Human Rights Clinic at Seattle University's law school - the U.S. Immigration and Customs Enforcement's operation at the Tacoma detention center is harshly criticized.

The report contains anecdotes in which detainees describe what they call degrading treatment by guards and subpar conditions at the jail.

"Probably the most striking, stark fact is that there's no accountability around conditions and standards, which is only made even more stark when you think of detention as being the fastest-growing form of incarceration in the United States," Pramila Jayapal, executive director of OneAmerica, said Monday.

Immigration officials denied the report's contentions, saying the detention facility complies with industry standards. The Geo Group, the Boca Raton, Fla.-based private contractor that runs the facility, declined comment Monday.

"The information contained in the report has numerous inaccuracies and vague references that could not be corroborated or independently verified," Immigration spokeswoman Lorie Dankers.

Most of the accounts come from 46 interviews between 2007 and 2008. Detainees were interviewed, as were family members and immigration lawyers. In some cases, researchers did not disclose names or dates in the accounts. The researchers also had sessions with ICE officials and tours of the facility.

One account in the 42-page report alleges that U.S. marshals denied some detainees access to restrooms for seven hours during flights from Seattle in 2007, leading some of the immigrants to defecate in their seats.

Melissa Middlesworth, a federal Justice Department spokeswoman based in Washington, D.C., said she could immediately comment on that allegation without closer examination of the report.

Another woman cited in the report said she was strip searched several times after visits with her lawyer. Dankers said thorough strip searches are uncommon and only done when officers think there's probable cause to conclude that inappropriate contact took place between a detainee and a visitor.

The report also alleged that many immigrants were pressured to sign documents they did not fully understand and faced verbal abuse from guards if they delayed. Also, a lack of meeting rooms for detainees and lawyers led to hurried meetings lacking privacy.

The detention center opened in 2004 and has been expanded twice. Dankers said the center typically runs near capacity, which is about 1,000 detainees. It houses detainees mainly from Alaska, Oregon and Washington.

OneAmerica included recommendations in its report for better treatment, including better attorney access, improved officer training, increased privacy and improved medical care.

The report came a few days after ICE announced an increase of nearly 40 percent in deportations out of Washington, Oregon and Alaska over the first nine months of the fiscal year. More than 7,300 people have been deported from the region in that period, immigration officials said.

© 2008 The Associated Press.