An international tribunal indicted Taylor, the former president of the West African nation of Liberia, for his role in bloody civil wars in his home nation and neighboring Sierra Leone.
Taylor is separately accused of harboring al-Qaida suicide bombers who attacked the U.S. embassies in Kenya and Tanzania in 1998 -- and killed 12 Americans and more than 200 Africans, according to the Associated Press.
Taylor fled from Liberia to Nigeria in 2003 after he stepped down as president as part of a deal to end Liberia's 14-year civil war. Since then he has lived in exile in a palatial compound.
Under mounting pressure from the United Nations, the United States and Liberia, Obasanjo agreed Saturday to extradite Taylor to the court in Sierra Leone. The U.S. State Department said that Nigeria was responsible for detaining and transferring Taylor.
Two days later, Taylor vanished. Officials are said to be investigating and according to the AP members of Taylor's Nigerian security unit have been arrested.
In Washington, White House spokesman Scott McClellan said the U.S. was seeking answers from the Nigerian government.
"Right now we are looking for answers from the Nigerian government about the whereabouts of Charles Taylor," McClellan said.
"It is the responsibility of the Nigerian government to see that he is conveyed to the special court for Sierra Leone," he added. "We expect the government of Nigeria to fulfill this commitment."
All this comes during Obasanjo's visit to the United States to meet with President Bush about Nigeria's decision to extradite the warlord, among other issues.
Obasanjo said the Nigerian government is creating a commission to investigate Taylor's disappearance.
Amnesty International has called for an international inquiry and said that any country that finds Taylor should send him to Sierra Leone.
Some analysts suggest, however, that Nigeria advocated Taylor's disappearance.
"'Allowing Charles Taylor to stand trial for war crimes sets a very controversial precedent for African heads of state and former heads of state because many of them ... have blood on their hands,' said Corinne Dufka of Human Rights Watch, Reuters reported.