WASHINGTON - Edging away from a close American ally, President Barack Obama prodded President Hosni Mubarak to take concrete steps and actions that deliver on reforms that the embattled leader promised in a speech early Saturday to Egyptians, suggesting that continued American support for his regime will depend on immediate action. Obama spoke by phone with Mubarak on Friday to deliver a stern message to the head of the government threatened by a rebelling public. Mubarak has promised a better democracy and greater economic opportunity, and I told him he has a responsibility to give meaning to those words; to take concrete steps and actions that deliver on that promise, Obama said. Obama said protesters grievances have built up over time because he has failed to address Egyptians desire for more open govt and improved economic opportunities. The US leader again called on the Egyptian govt to show restraint in keeping order, and he also emphasized that demonstrators have a responsibility to protest peacefully. Violence and destruction will not lead to the reforms that they seek, he said. This moment of volatility has to be turned into a moment of promise, Obama said in a televised appearance from the White House. Surely, there will be difficult days to come, but the United States will continue to stand up for the rights of the Egyptian people and work with their government in pursuit of a future that is more just, more free and more hopeful, Obama said. Mubarak, in his first public appearance since the tens of thousands of protesters took to the streets, said he understood Egyptians hardships. He announced that he was firing his government, but he did not offer to step down as the demonstrators have demanded. In another move to raise pressure on the Mubarak government, US officials Friday threatened to cut the $1.5 billion in US aid to Egypt if the government did not heed its calls to avoid violence against the protesters. Violence in any form needs to stop, and grievances need to be addressed, said Robert Gibbs, White House press secretary. We will be reviewing our posture based on events in the coming days. Aid is Washingtons greatest leverage in the three-decade US-Egyptian alliance. Analysts said the threat was aimed not only at Mubarak but also at Egypts military leaders, who depend heavily on the money for basic operations. The aid package is $1.3 billion in military assistance and about $250 million in economic assistance. This is a warning to the military: You guys be careful; we could pull the plug, said Edward Walker, a former US ambassador to Egypt. This is very serious. Mubarak on Friday sent the military into the streets, where soldiers were cheered by protesters who had clashed with police officers and security forces. US observers said they had not witnessed any unwarranted actions by the military. Theyre a professional military with whom we have close ties, and we see no indication that they are acting in any other way but professionally, at this point, said a senior Pentagon official who spoke on condition of anonymity. The protests in Egypt forced Lt. Gen. Sami Hafez Enan, the chief of staff of the Egyptian armed forces, to cut short meetings in Washington, according to a statement released Friday by the Pentagon. Enan and a delegation of 25 Egyptian officers had been scheduled to attend meetings in Washington until Wednesday as part of a regular set of discussions between defence officials in both countries. The talks were adjourned Friday after the Egyptian delegation was called home by its government, according to the Pentagon. Before Enans departure, Alexander Vershbow, the assistant secretary of Defence for international security affairs, urged Egypts military not to use unnecessary force. The current situation in Egypt arose very quickly, but Ambassador Vershbow did have the opportunity to urge restraint to his Egyptian counterpart during the Wednesday and Thursday meetings here in the Pentagon, the statement said. A senior Defence official said other US civilian and uniformed officials contacted Egyptian counterparts Friday to repeat the same message: It would be unwise for the Egyptian armed forces to use force. We will support you, but it would be in everybodys best interest if anything you do is non-violent, said the US official, describing the theme of the Pentagon advice to the Egyptian military. The Egyptian government, however, ignored US warnings to stop interfering with the Internet access and social network websites, such as Facebook and Twitter, that protesters had been using to communicate. There also was no sign that Egyptian authorities intended to lift the house arrest of opposition leader and Nobel laureate Mohamed ElBaradei despite the White Houses expressions of support for him. Obama administration officials have been increasingly positive toward the protesters with each day, even while continuing to express some backing for the Mubarak government, a key ally in the region. Before the unrest broke out, the administrations strategy had been to push for gradual internal reforms in Egypt and avoid chaotic change that could leave the country in the hands of new leaders less friendly to the United States. But as thousands of protesters clashed this week with authorities in cities across Egypt, Secretary of State Hillary Rodham Clinton began pressing Mubarak to act more quickly. Clinton said reform was absolutely critical to the well-being of Egypt and urged the government to engage immediately with opposition groups. Obama spent a substantial part of Friday being updated on developments in Egypt, including holding conversations with the US ambassador in Cairo, Margaret Scobey, aides said. David Axelrod, the presidents senior advisor, said Friday that although the ultimate outcome of the Egyptian protests wasnt easy to predict, Obama had repeatedly warned Mubarak that the political status quo was not tenable. Its fair to say that weve raised concerns about the political situation in Egypt and the treatment of people for some time, Axelrod said. So in that sense, no, I cant say that its a total surprise. In certain ways you could see this coming. But you never knew what the breaking point would be. The president has had a consistent dialogue with President Mubarak on issues of democracy and reform and his belief that the universal rights of people in Egypt needed to be respected and urging a process for that to happen.