Different groups of detainees were released at various stages, often dependent upon their nationality, but also including criteria such as ill health and the body of one individual who had died during captivity. While some passengers were detained only for a few weeks, others were detained for months, often in poor conditions. Former British prime minister Edward Heath travelled in person to Baghdad for direct talks with Iraq's President Saddam Hussein, and is credited with leading negotiations to successfully release the hostages taken. During mid December 1990, the last of the remaining American and British hostages were released by Iraq.