S. Sudan's Kiir Ready for Talks with Machar 'Without Preconditions,' Says U.S. Envoy

South Sudan's President Salva Kiir has said he is ready for talks with rival Riek Machar "without preconditions," the U.S. special envoy to the violence-wracked country, Donald Booth, said Monday.

"I had a frank and open discussion with President Salva Kiir," Booth, in Juba, told reporters in Washington.

"Importantly, President Kiir committed to me that he was ready to begin talks with Riek Machar to end the crisis without preconditions as soon as his counterpart is willing."

Booth, who is also the U.S. special envoy for Sudan, said he met with a group of 11 senior figures in the ruling Sudan People's Liberation Movement "who remain detained in Juba."

Kiir's government last week announced the arrest of 10 people, many of them former ministers, in connection with an investigation of an alleged coup attempt led by Machar against Kiir.

"I can report that they are secure and well taken care of," Booth said.

"These individuals communicated to me their desire and their readiness to play a constructive role... for peaceful political dialogue and national reconciliation."

South Sudan's army on Monday was poised for a major offensive against rebel forces, as the country slid towards civil war despite international peace efforts.

The U.N. Security Council was set to hold emergency talks on the situation later Monday, at 2200 GMT. U.N. Secretary General Ban Ki-moon has called for the reinforcement of the U.N. mission in South Sudan.

The Pentagon said earlier that the U.S. military was redeploying aircraft and other forces in the Horn of Africa to prepare for possible further evacuations of Americans from South Sudan.