"Our understanding is, like the others, he's being detained in a state guest house and that it is appropriate that Niger and the TNC work through this together," spokeswoman Victoria Nuland told reporters in Washington, referring to the National Transitional Council, Libya's interim government.
"It's essentially a house arrest in this government facility, is our understanding," she said.
Saadi, 38, the third of Kadhafi's seven sons, arrived in Niger, one of the west African countries that benefited the most from Kadhafi's largesse, on Sunday in a convoy alongside other members of the toppled regime.
Seen as something of a playboy, Saadi was hired in 2003 to play for Italian first division football club Perugia but barely kicked a ball when he was suspended after testing positive for nandrolone, an anabolic steroid.
He renounced his football career the following year to join the Libyan army, where he led an elite unit.
Copyright AFP (Agence France-Presse), 2011
Copyright APP (Associated Press of Pakistan), 2011