Leading opposition figure Mohammed ElBaradei said Friday that Egypt is now a free and proud nation, dpa reported.
"Egypt today is a free and proud nation. God bless," wrote ElBaradei on Twitter just minutes after Hosny Mubarak resigned as president following 28 years in power.
The Nobel Peace Prize laureate and former head of the UN nuclear watchdog agency was a leading member of the opposition coalition calling for the ouster of Mubarak.
Google employee Wael Ghonim, who roused thousands to join protests this week after his release from prison, wrote on Twitter "I want to thank Mohammed ElBaradei as his arrival to Egypt was what got me interested in changing."
Ghonim is believed to be behind the January 25 Facebook page that helped to kickstart nationwide protests.