Egypt's banned Muslim Brotherhood, part of a mass protest demanding the ousting of President Hosni Mubarak, will start landmark talks with the recently named vice president on Sunday, it said.
"We will join the talks today," Essam el-Erian told AFP, referring to talks between Vice President Omar Suleiman and opposition groups 'to discuss an interim period and electing a new parliament representing the people'.
The meeting was to take place before noon (1000 GMT), according to Erian.
He said the Islamist group had agreed to join talks between the authorities and opposition groups, but warned it would drop out if there is no one to represent the young protesters who have occupied Cairo's Tahrir Square.
"We have been invited. We will go. But our participation is conditional on giving the youth representation," he said. "If the demands of the youth are not met, we have the right to reconsider our position."
The group said earlier that it was entering talks with the authorities in the interest of the people, on the 13th day of a mass rally at Tahrir Square demanding a regime change and Mubarak's departure.
"Keeping in mind the interests of the nation and its institutions and concerned about preserving the country's independence... we decided to begin talks to see up to what point they are ready to accept the demands of the people," a Brotherhood official told AFP on condition of anonymity.
For his part, Suleiman had said earlier that an invitation for dialogue between the government and opposition groups had been extended to the Muslim Brotherhood group, but said that the Brothers were "hesitant."
The Brotherhood is Egypt's best-organised opposition movement drawing on a vast social aid network.
Senior members of Mubarak's party resigned on Saturday, but demonstrators remained barricaded in the square, rejecting the shuffle as a cosmetic move.
At least 300 people are believed to have been killed and thousands injured since the protests began on January 25, according to the United Nations high commissioner for human rights.