Foreign observers estimate that hundreds of thousands and perhaps millions of Falun Gong practitioners have been detained in "re-education through labor" camps, prisons and other detention facilities for refusing to renounce the spiritual practice. Former prisoners have reported that Falun Gong practitioners consistently received "the longest sentences and worst treatment" in labor camps, and in some facilities Falun Gong practitioners formed the substantial majority of detainees. As of 2009 at least 2,000 Falun Gong adherents had been tortured to death in the persecution campaign, with some observers putting the number much higher.