NBC's Richard Engel said two independent sources had confirmed that Mubarak would step down and Vice President Omar Suleiman would take over. CNN reported that CIA Director Leon Panetta also expected Mubarak to resign Thursday.
In addition, the armed forces supreme council had convened to begin the orderly transition of power.
Earlier Thursday, Gen. Hassan al-Roueini, a military commander, told thousands of protesters in central Tahrir Square: "All your demands will be met today."
Many among the flag-waving protesters held up a V-for-victory sign and shouted, "Allahu akbar," or "God is great," the Associated Press reported.
Meanwhile, the head of the ruling party, Hossam Badrawi, told the Associated Press that Mubarak would "address the people tonight to respond to protesters demands."
A statement by the armed forces on Egyptian state TV said the military convened the supreme council of the armed forces "to safeguard people and protect their interest." Al-Jazeera TV noted that Mubarak was not shown attending that meeting.