Egyptian President Hosni Mubarak is to stand down in September.

The 82-year-old leader has announced he will not seek re-election when his presidential term ends in September. "I will work in the remaining months of my term to take the steps to ensure a peaceful transfer of power," he said in a televised address.

His ten-minute speech was greeted with dismay among protesters whose numbers swelled above 1 million across Egypt on Tuesday after week-long demonstrations.

And to those demanding he leave Egypt, he said, "This is my country ... and I will die on its soil."

Washington, which has been caught off guard by the wave of anger over oppression and hardship which has spread from Tunisia to one of its closest Arab allies, added pressure on Mubarak to speed up his response while stopping short of calling on him to quit.

"What is clear and what I indicated tonight to President Mubarak is my belief that an orderly transition must be meaningful, it must be peaceful and it must begin now," President Barack Obama said after speaking to him by phone.

But inside Egypt the immediate future remained unclear. Soon after Mubarak's speech, state television, which had largely ignored anti-government protests, broadcast footage of smaller demonstrations held in support of the president.

At Cairo's Tahrir, or Liberation, Square, focus of protests for a week, people defying a curfew bitterly criticised Mubarak for failing to heed their call for him to quit.

In Alexandria, the second city, troops in tanks fired shots in the air to keep order after skirmishes between anti-government and pro-Mubarak groups.