"President Mubarak did not understand the message of the Egyptian

people," ElBaradei said. "His speech was totally disappointing. The protests will continue with even more intensity until the Mubarak regime falls."

The Nobel laureate and former chief of the UN nuclear watchdog returned to Cairo from Vienna in time to join massive protests on Friday across Egypt that shook the world's most populous Arab nation and prompted Mubarak in a speech early on Saturday to promise reforms.

"I will go back into the streets today (Saturday) with my colleagues to contribute to bringing change... and to tell President Mubarak that he must go," ElBaradei said.

"When the regime behaves so lowly, and opens fire with a water cannon on someone who has received the Nobel prize, it indicates the beginning of the end for the regime and it must go," he added.

During Friday's protests, police used tear gas, water cannons and rubber-coated bullets against thousands of demonstrators who rampaged through the streets of Cairo.

Reports said ElBaradei was drenched by a water cannon and prevented by police from leaving a mosque in which he took shelter.

In Saturday's television interview, the Nobel laureate could not confirm reports that he was under house arrest.

"There are no troops stationed outside my house," he said. "I will verify that when I go out today. But I really don't know how accurate it is. I think in my view it's probably a message sent to discourage people from participating in the peaceful demonstrations."

He gave the interview as thousands of anti-regime demonstrators poured onto Cairo's streets for as fifth straight day demanding Mubarak's ouster.

Angry citizens streamed into Tahrir square, a focal point for the protests and street battles that have raged since Tuesday, chanting: "Mubarak out!" as troops looked on.

Mubarak, 82, addressed the nation overnight, sacking the government and vowing economic and political reforms in the world's most populous Arab nation but showing no sign of easing his decades-old grip on power.

"I have asked the government to resign and tomorrow there will be a new government," a stony-faced Mubarak said amid the worst protests since 1977 bread riots.

"We will not backtrack on reforms. We will continue with new steps which will ensure the independence of the judiciary and its rulings, and more freedom for citizens," he said.

Protesters who have been demanding that Mubarak step down, as well as an end to endemic state corruption and police brutality that have become systematic under his rule, dismissed his speech as too little, too late.

ElBaradei described the speech as an "empty statement."

"Last night's expectation was that he would have decided to leave and then we start a new process but at the last minute he came out with an empty statement which was a huge disappointment to the Egyptian people."

"He obviously did not understand the message from the Egyptian people. It was almost an insult to the intelligence of the Egyptian people to tell them that the only response is that I will have a new government ... He did not elaborate on one single economic or social reform."

ElBaradei vowed to press on with attempts to force Mubarak to step down.

"I will continue to participate in whatever it takes to make sure that the Mubarak regime should leave," he said.

"I think that there is a consensus here in Egypt in every part of society that this is a regime that is dictatorial, that has failed to deliver on economic, social or political fronts and that we need a new beginning, an Egypt that is free, that is democratic and we need to go through a transitional period.