Protesters had packed Cairo's Tahrir Square by mid-day Tuesday, standing shoulder-to-shoulder as large groups still streamed into area for the planned "march of millions." Soldiers stood guard and helicopters hovered overhead as demonstrators gathered to demand President Hosni Mubarak's resignation. Egypt's government posted troops at key locations and cut internet service as activists pledged to hold major demonstrations in Cairo, Alexandria and other cities Tuesday -- a week after rallies began calling for an end to Mubarak's nearly 30-year rule. In Cairo, protesters set up their own checkpoints to keep weapons out of Tahrir -- or Liberation -- Square. People brought food and beverages to share. Families stood together, with parents saying they came for their children. One group chanted "Down with Mubarak," while others listened to patriotic music. Soldiers at a security checkpoint outside the square said demonstrators supporting Mubarak were also in the area, which has been a focal point of anti-government protests.