CAIRO?(UPDATE) Astonished and elated Egyptians poured into the streets across their nation on Friday, dancing, cheering and crying as they celebrated the long-awaited ouster of president Hosni Mubarak.

A wave of joy swept across the country, with people rushing from their homes and offices to join the spontaneous street party, an expression of nationwide relief at the collapse of the only regime many Egyptians have ever known.

People called friends and clutched strangers to offer their congratulations at the end of the strongman's 30-year rule.

In the minutes after the announcement was made, cars sped across the bridges crossing the river Nile, honking their horns in celebration, their drivers leaning out of windows to spread the news.

"He's gone! He's gone! It's finished!" one man shouted to passers-by.

In Cairo, people flooded towards the city's central Tahrir Square, the epicentre for 18 days of protests against Mubarak's regime.

Inside, people could barely move except to clap along to chants, sing the national anthem, and lift their camera phones to snap pictures of fireworks shooting into the air over the crowd.

It was the party they had been promised a day earlier, when hundreds of thousands had gathered in Tahrir Square to hear Mubarak deliver an address that was expected to be his resignation speech.

Instead, he announced he would transfer some powers to his vice president but remain in office, prompting fury among the demonstrators.

But the speech that so disappointed the masses on Thursday did turn out to be Mubarak's last as president. Announcements that the army was taking power and Mubarak would step down came from the military and vice-president.

In Tahrir, the crowd roared "the people have overthrown the regime" and "lift your heads up high, you're Egyptian," proud that their country had joined the "free world."

"Now the Egyptians have their freedom," said Mohammed Gamal, a 21-year-old Cairo University student. "We broke down the wall of fear. We changed our people."

Many expressed shock at the speed of Mubarak's departure, just 18 days after the start of massive protests inspired by the popular revolt that chased Tunisia's strongman Zine El Abidine Ben Ali into exile after a 23-year reign.

"Who would have thought we could finish the job in such a short time?" shouted Ahmed Zahran, a protest organiser and cyber activist, as he joined the raucous party in Tahrir.

"We had been so depressed and so unsure. This is the happiest moment of my life," he said. "This is the happiest day for everyone in Tahrir Square and in Egypt."

Outside the main presidential palace in the Heliopolis neighbourhood protesters shouted "God is greatest!" as they hugged one another, danced and ululated. Some fell to the ground, overcome with emotion.

Elsewhere in Cairo, gunshots and the enthusiastic car horn honking usually reserved for weddings were heard as Egyptians celebrated Mubarak's resignation.

At one roundabout, jubilant Egyptians clambered on top of army tanks, almost every inch of the military vehicles taken up by flag-waving citizens desperate to have their picture taken with grinning soldiers.

On the roads, young men sat and stood on cars, trucks and buses, patriotic music blaring from their radios, many of them wiggling their hips and clapping to the beat.

The country's most organised opposition movement, the Muslim Brotherhood, hailed the departure of Mubarak, whose regime had banned but tolerated the Islamist group while arresting and mistreating thousands of its members.

"We salute the great people of Egypt in their battle," Essam al-Erian, a senior Brotherhood leader and spokesman, told AFP.

"We salute the army, which kept its promises... We celebrate this moment with the Egyptian people, and we will follow the people in this course."

Top opposition figure Mohamed ElBaradei on Friday called Egypt "a free and proud nation" on the micro-blogging website Twitter.

As they basked in the glow of Mubarak's departure, some protesters admitted some worry about whether the revolt would achieve its larger goal of replacing the regime with a democracy.

"I don't think it's my last night in Tahrir. Until now we've had no news on what's happening outside Cairo," said 22-year-old Hani el-Qadi, a credit officer. "We need to know everything. I'm still cautious."

But despite his caution, he said he could not help but be excited.

"This is a success for us, but this is the first step."