Some tweets from the last few minutes...

Scale of fighting is "stunning" says CNN's Ivan Watson

right in the middle of the clashes. my cameraman is bloodied. utter CHAOS right now! #egypt #jan25

Al Jazeera: Journalist: "There are people atop buildings around Meydan Tahrir throwing fire bombs at protesters

Overheard army officer off Tahrir square. They have no strategy to deal with situation. they are watching passively. #Egypt #Jan25

Horrible: Molotov cocktails being thown from rooftops onto anti-govt. demonstrators #egypt

Protestors now surrounded by Pro-Mabarak supporters, trapped in Tahiri Sq, armed with petrol bombs fighting for their lives...