The first senior U.S. official to visit Egypt since the army toppled its elected president was snubbed by both Islamists and their opponents on Monday.
Deputy Secretary of State William Burns arrived in a divided capital where both sides are furious at the United States, the superpower which supports Egypt with $1.5 billion in annual aid, mostly for the army that deposed Islamist President Mohamed Morsi two weeks ago.
Crisis in the Arab world's most populous state, which has a peace treaty with Israel and controls the strategic Suez Canal, has alarmed allies in the region and the West. Thousands of supporters of the ousted leader took to the streets on Monday.
Washington, never comfortable with the rise of Morsi's Muslim Brotherhood, has so far refused to say whether it views Morsi's removal as a coup, which would require it to halt aid.
The State Department said Burns would meet "civil society groups" as well as government officials, but the Islamist Nour Party and the Tamarud anti-Morsi protest movement both said they had turned down invitations to meet Burns.
"First, they need to acknowledge the new system," Tamarud founder Mahmoud Badr said of the Americans. "Secondly, they must apologize for their support for the Muslim Brotherhood's party and terrorism. Then we can think about it," he told Reuters.
In a further slight, Badr posted a copy of his invitation, including the U.S. embassy's telephone number, on the Internet.
Nour, sometime allies of Morsi's Brotherhood who have accepted the army takeover, said they had rejected meeting Burns because of "unjustified" U.S. meddling in Egypt's affairs.
The Brotherhood's political party said it had no meeting planned with Burns. It was not immediately clear whether it was invited. While its opponents accuse Washington of backing Morsi, the Brotherhood suspects U.S. involvement in his removal.
Burns did meet Adli Mansour, a judge installed as interim president by the army, and Hazem el-Beblawi, a liberal economist named interim prime minister. Beblawi is setting up a temporary cabinet staffed mainly by technocrats to lead the country under a "road map" foreseeing elections in about six months.
Islamists, who have maintained a vigil demanding Morsi be reinstated, called a mass protest for Monday. Demonstrations in Cairo have been largely peaceful for the past week after at least 92 people were killed in the days after Morsi was toppled.
Two rows of armored personnel carriers were in place near the mosque square in northeast Cairo where Morsi supporters have maintained their vigil. Barbed wire was blocking the street leading from the protest site to the Republican Guard barracks, scene of the worst violence a week ago when uniformed snipers were filmed firing from the rooftops into crowds.
As thousands of protesters assembled on Monday, a group of women clapped and chanted: "Down with the military regime! Down with the dictator! President Morsi, no one else!"
Demonstrators fasting for the holy month of Ramadan rested in the shadow of tents reading the Koran. Army helicopters had flown above overnight, dropping fliers exhorting the crowd to renounce violence and end their sit-in.
Abdel Khalid Abu Zeinia, a 50-year-old accountant camped at the square for 11 days in support of Morsi, said of Burns's visit: "America works against the Egyptian people's interests. America's only concern is its interests, and Israel's. America offers only words, not practical support to democracy."
If Burns drove through downtown a few miles away, he might have seen a giant banner with a portrait of U.S. ambassador Anne Patterson and the message "Go home, witch!". It was hung by Morsi's foes, who are as angry with America as his supporters.
Morsi is being held incommunicado at an undisclosed location.
He has not been charged with a crime but the authorities say they are investigating him over complaints of inciting violence, spying and wrecking the economy. Scores of Morsi supporters were rounded up after violence last week.
Most of the top Brotherhood leaders have been charged with inciting violence but are still at large with the police not following through on arrest warrants.
Morsi's foes have also called for a demonstration on Monday, but their rallies have become sparsely attended since they achieved their objective of bringing him down.
Beblawi has been naming ministers for his interim cabinet, including a former ambassador to the United States as foreign minister, a sign of the importance Cairo places in its relationship with its superpower sponsor.
U.S.-educated economist Ahmed Galal, as finance minister, has the task of rescuing an economy and state finances wrecked by two and a half years of turmoil.
That task became easier, at least in the short term, after Saudi Arabia, the United Arab Emirates and Kuwait, Arab states happy at the downfall of the Brotherhood, promised a total of $12 billion in cash, loans and fuel.
The new planning minister, Ashraf al-Arabi, an economist who also served in that role for a time under Morsi, said the Arab money would be enough to sustain Egypt through its transition period, and it was "not appropriate" now for Egypt to restart talks with the International Monetary Fund.
Egypt had sought $4.8 billion in IMF aid last year, but months of talks ran aground with the government unable to agree steep cuts in unaffordable food and fuel subsidies. Arabi's comments could worry investors who want IMF talks as a spur to prod Egypt to make economic reforms.
"It think it's inappropriate to be making such a strong statement, given how new he is to the position," Angus Blair, president of Signet Institute, an economic think-tank for the Middle East and North Africa, said of Arabi's remarks.
"I think it would encourage all investors if the IMF funding and its additional contingent aid would be viewed as part of the overall financial equation for Egypt. There's so much to be done to boost economic growth."
Beblawi also placed a police general in charge of the supply ministry which manages the huge distribution network for subsidized goods, a sign the government may focus on cleaning up a notoriously corrupt system.
A lack of clarity over the U.S. position has fueled anti-Americanism on both sides. U.S. ambassador Patterson angered Morsi's enemies in the weeks before he was ousted by emphasizing his electoral legitimacy and discouraging protests against him.
Last week, the State Department further muddied the waters by saying Morsi's rule was undemocratic, a comment interpreted in Cairo as implying his removal was legitimate. Washington has also called for him to be freed and political detentions halted.
"The goal of his trip is to engage with and hear directly from interim Egyptian officials and civil society as part of our ongoing efforts to see Egypt transition to an inclusive, pluralistic, democratically elected civilian government," State Department spokeswoman Jen Psaki said ahead of Burns's trip.
The interim authorities say the new government is open to all, including even the Brotherhood, an invitation spurned by Morsi's backers who refuse to have any dealings with "usurpers".
The political turmoil and unrest in major cities has also fueled violence in Egypt's lawless North Sinai province bordering Israel and the Palestinian Gaza Strip, where Islamist militants have called for people to rise up against the army.
A series of attacks in the area have claimed at least 13 lives, mainly security personnel, since July 3. In the latest assault, suspected militants fired rocket-propelled grenades at a bus carrying workers from a cement factory in the Sinai city of El Arish, killing three and wounding 17.
Additional reporting by Peter Graff, Shadia Nasralla, Noah Browning, Ulf Laessing, Ali Abdelaty, Patrick Werr and Mike Collett-White in Cairo and Arshad Mohammed in Washington; Writing by Peter Graff; Editing by Alastair Macdonald