"Coalition forces will continue to retain physical custody of the defendants until this issue is resolved," she said.
Al-Maliki on Sunday accused the US embassy of playing an "unfortunate role" in preventing the handover of the three condemned men who are in US military custody.
He told a press conference in Baghdad that his government was "determined" that the executions be carried out.
Ali Hassan al-Majid, widely known as "Chemical Ali" for his use of poisonous gas against the Kurds along with Sultan Hashim al-Tai, Saddam's defence minister and Hussein Rashid al-Tikriti, his armed forces deputy chief of operations, were sentenced to death on June 24.
hey were found responsible for the slaughter of thousands of Kurds in the so-called al-Anfal (Spoils of war) campaign of 1988.
"There continue to be differences in viewpoint within the government of Iraq regarding the necessary ... requirements for carrying out death sentences"
Mirembe Nantongo, US spokeswoman
Under Iraqi law, the men were scheduled to be executed by October 4, 30 days after their sentences were upheld by the Iraq supreme court.
But al-Maliki made it clear he did not want the executions to take place during the Muslim holy month of Ramadan, which ended on October 15, because of the outcry that followed Saddam Hussein's execution during another Muslim holiday.
More than a month after the deadline the sentences have not yet been carried out and lawyers now claim that executing the men would be illegal.
Further complicating matters, Jalal Talabani, the Iraqi president, and Tareq al-Hashemi, the vice president, have refused to sign the execution order.
Talabani, who is opposed in principle to the death penalty, refused to give the order but signed a letter to al-Maliki saying he would raise no objections if the government went ahead.
Al-Hashemi fears that the execution of Hashim could undermine reconciliation efforts in post-Saddam Iraq.