Clashes broke out between opponents and supporters of President Hosni Mubarak in central Cairo on Wednesday after the armed forces told protesters clamoring for an end to his rule that they must clear the streets, witnesses said.

The fighting broke out as international pressure grew on Mubarak to quit and his closest ally, the United States, told him bluntly that a political transition must begin immediately.

After Mubarak went on national television on Tuesday night to say he would not stand in elections scheduled for September, the armed forces said the protesters' demands had been heard and it was time for them to clear the streets.

Soon after several hundred pro-Mubarak supporters entered Tahrir (Liberation) Square, where a few thousand protesters had gathered, and clashes broke out, witnesses said.

People fought each other with sticks and stones while troops surrounding the square made no attempt to intervene, witnesses said.

It was the ninth day of protests that erupted last week as public frustration with corruption, oppression and economic hardship under 30 years of rule by Mubarak boiled over.

A military spokesman, addressing the protesters on state television on Wednesday morning, said: "The army forces are calling on you. You began by going out to express your demands and you are the ones capable of restoring normal life."

Although the army had previously said the people had "legitimate demands" and soldiers would not open fire on them, it was a clear call for protesters to leave the streets An opposition coalition, which includes the Islamist organization the Muslim Brotherhood and Nobel peace laureate Mohammed ElBaradei, responded by calling for more protests.

It said it would only negotiate with Vice President Omar Suleiman, a former intelligence chief appointed by Mubarak at the weekend, once Mubarak stepped down. Mubarak's offer to leave in September was his latest gambit in the crisis.

At the weekend he reshuffled his cabinet and promised reform but it was not enough for protesters. One million people took to the streets of Egyptian cities on Tuesday calling for him to quit.

Cut and Clean

International backing for Mubarak, for three decades a stalwart of the West's Middle East policy and styled as a bulwark against the spread of militant Islam, has crumbled as he tried to brazen out the crisis.

U.S. President Barack Obama spoke to Mubarak for half an hour by telephone on Tuesday night after the 82-year-old strongman announced his plan to step down in September.

"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," Obama said after speaking to him.

Pressure also came from Turkey, an important diplomatic voice in the Muslim world. Prime Minister Tayyip Erdogan said Mubarak's plan to step down in seven months time did not meet the people's expectations and the change should begin sooner.

France, Germany and Britain also called for a speedy transition. "The transition needs to be rapid and credible and it needs to start now," British Prime Minister David Cameron told the UK parliament.

Some of the few words of encouragement for him have come from oil-giant Saudi Arabia, a country seen by many analysts as vulnerable to a similar outbreak of discontent.

Israel, which signed a peace treaty with Egypt in 1979, is also watching the situation in its western neighbor nervously, weighing the possibility that anti-Israeli Islamists might gain a share of power.
Yemen, Jordan Feel the Heat.

Many analysts see the army as trying to ensure a transition of power that would allow it to retain much of its influence.

But some said tensions could rise even within the army if Mubarak were to hang on too long, and if senior officers were seen to be protecting a leader who had lost legitimacy.

"The longer this goes on, the more people will associate the military top brass with Mubarak. That is very dangerous," said Faysal Itani, a Middle East expert at Exclusive Analysis.

The uprising was inspired in part by a popular revolt in Tunisia last month which overthrew long-ruling President Zine al-Abidine Ben Ali. The mood is spreading across the region.

King Abdullah of Jordan replaced his prime minister on Tuesday after protests there.

Yemeni President Ali Abdullah Saleh, a key U.S. ally in the fight against al Qaeda, said on Wednesday he would not seek to extend his presidency, a move that would end his three-decade rule in 2013.

Oil prices continued to climb on Wednesday on worries that unrest in Egypt would trigger regime change across the Middle East and North Africa, driving North Sea Brent crude towards a 28-month high.

But with Mubarak pledging to go, foreign investors have begun to show renewed interest in Egyptian bonds and stocks.