Egyptian President Hosni Mubarak overhauled his government on Monday to try to defuse a popular uprising against his 30-year rule but angry protesters rejected the changes and said he must surrender power.

On the seventh consecutive day of unrest in the Arab world's most populous nation, tens of thousands of protesters rallied in Cairo's Tahrir Square chanting Get out ... We want you out and singing Egypt's national anthem.

Troops backed by tanks and armoured personnel carriers made no effort to disperse the crowd even two hours after a curfew started, although helicopters flew overhead.

This is all nonsense, said protester Omar el-Demerdash, 24, a research executive, adding:

The demand is clear: We want Mubarak and his men to get out. Anything other than that is just not enough.

Egypt's powerful army now appears to hold the key to Mubarak's fate. Although the generals have held back from crushing the revolt, they have not withdrawn support for him.

The uprising, unprecedented in scale and intensity in this once tightly-controlled country, erupted last week when frustration over repression, corruption, poverty and the lack of democracy under Mubarak boiled over.

About 140 people were killed in clashes with security forces in scenes that overturned Egypt's standing as a stable country, promising emerging market and attractive tourist destination.

Mubarak, a close U.S. ally and a stalwart in Western policy towards the Middle East, responded by offering economic reform to address public anger over hardships.

REPRESSIVE TACTICS

On Monday he named General Mahmoud Wagdy, previously head of Cairo criminal investigations department, as the new interior minister. Wagdy's predecessor was reviled by many Egyptians because of the repressive tactics used by the police force to quash the opposition and criticism of the president.

Mubarak, clinging to power as his legitimacy vaporises, on Saturday named his intelligence chief, Omar Suleiman, a former military man, as vice president, a post vacant for 30 years. It was a move seen by some as a prelude to a transition in power.

He also appointed former air force commander Ahmed Shafiq as prime minister after sacking the entire cabinet.

But it appeared the moves would do little to turn back the groundswell against the 82-year-old ruler.

This new cabinet is too little, too late. I think Mubarak will probably be gone well before 30 days is up, Zaineb Al-Assam, a Middle East expert at London-based Exclusive Analysis, told Reuters.

There are some figures in the cabinet who are deeply unpopular. An example is General Wagdy. That's going to add to the protests. Mubarak will be seen by the army as a liability.

Dave Hartwell, Middle East analyst at IHS Jane's, said the goverment changes ruled out the possibility that Mubarak's son Gamal -- until last week widely viewed as his likely successor -- would take over.

The speculation is these changes are being forced on Mubarak by the army and the conclusion is the army is now wielding influence behind the scenes.

Protesters called for mass rallies on Tuesday, saying one million people could take to the streets to mark a week since the uprising broke out.

Although the movement started with no clear leaders or organisation, the opposition is taking steps to organise.

The Muslim Brotherhood, an Islamist group, said it was seeking to form a broad political committee with Mohamed ElBaradei to talk to the army.

ElBaradei, a Nobel peace laureate and former head of the U.N. nuclear agency, has urged Mubarak to go and has lent his international stature to a movement that has lacked a leader.

The Brotherhood, which has wide support among poor Egyptians, has until now kept in the background of an uprising spearheaded by the young urban poor and students, fearing a harsh crackdown.

WEST WAIT-AND-SEE

World leaders were trying to figure out how to respond to a crisis that threatens to tear up the Middle East political map.

Most have urged Mubarak to introduce reforms but stopped short of calling for him step down, preferring to emphasise their desire for stability and democratic elections.

The United States, which has poured billions of dollars of aid into Egypt since Mubarak came to power has called for an orderly transition.

Washington has long seen Mubarak as a bulwark in the Middle East, first against communism then against militant Islam.

As the first Arab nation to sign a peace treaty with Israel, Egypt plays a key part in the peace process, and a change in leadership could have big implications for these efforts.

We certainly don't want Egypt to fall into the hands of extremists, British Foreign Minister William Hague said in Brussels. That is why we want an orderly transition to free and fair elections.

The crisis in Egypt follows a revolt that toppled the leader of Tunisia earlier this month and the wave of popular anger is also sweeping other countries in North Africa and the Middle East. It was the generals who persuaded Tunisia's leader to go.

Exclusive Analysis' Assam said Yemen, Sudan, Jordan and Syria all looked vulnerable to contagion but the greatest risk was in Saudi Arabia.

U.S. interests are the first casualty. Indeed, U.S. allies in the region will be alarmed at the rapid drain of U.S. public support for an erstwhile ally like Mubarak, she said.

Syria's President Bashar al-Assad said there was no chance the upheaval might spread to Syria, which has been controlled by his Baath Party for the last five decades.

In an interview with the Wall Street Journal, Assad said Syria's ruling hierarchy was very closely linked to the beliefs of the people and that there was no mass discontent.

TUMULT HITS TOURISM

Foreign governments scrambled to ensure the safety of their nationals trapped by the unrest. One group of tourists was hunkered down in the Marriott Hotel in the Egyptian capital waiting to be taken to the airport.

I had heard a lot about Egypt's history and the pyramids so I am very disappointed I cannot see all that, but I just want to get out, said Albert So, an accountant from Hong Kong.

Egypt's financial markets and banks were closed for the second day in a row.

International markets are also watching anxiously. Global stocks flattened out after opening down and developed market stocks were up.

Europe's benchmark Brent crude was just short of $100 a barrel on fears the unrest could spread among regional oil-producing nations.

Moody's downgraded Egypt to Ba2 with a negative outlook from Ba1, saying the government might damage its already weak finances by increasing social spending to calm the protests.