Senior Egyptian military officers visited the United States Monday for talks as both sides try to defuse a deepening row that has seen a number of American citizens hole up at the US embassy in Cairo.
Egypt's military rulers, charged with leading the transition to democratic rule, have slapped a travel ban on several US citizens working for pro-democracy non-government organizations (NGOs).
US State Department spokeswoman Victoria Nuland confirmed that "a handful" of Americans barred from leaving had taken shelter at the American mission while awaiting Egypt's permission to depart.
In what would be a dramatic sign of a fraying alliance -- one that has been the lynchpin of US diplomacy in the Middle East -- The Washington Post and The New York Times quoted officials saying the Americans feared arrest.
Nuland said a high-ranking Egyptian military delegation was in the United States this week for talks with officials from the Pentagon, the State Department and Congress.
Although it was a previously scheduled trip, the row over the NGOs will come up during these meetings, she added.
A State Department official told AFP the Egyptian officers had arrived Monday in Tampa, Florida -- headquarters for US Central Command, which oversees the Middle East. They were due to leave Tampa for Washington on Wednesday.
Nuland said the embassy had invited the Americans to stay because they had "concerns" she would not specify, although she made clear that "we do not feel that they are in physical danger at the moment."
She added: "That is a different matter than whether they are being persecuted in the Egyptian judicial system."
Daniel Kurtzer, a former US ambassador to Egypt, told CNN television the decision to shelter the NGO members was a smart move.
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"Nobody is claiming these folk will face mortal danger if they leave the embassy and they're there by invitation. So it's a clever act by the embassy to remove the immediate precipitant," Kurtzer said.
White House spokesman Jay Carney said the US has made clear to Egypt's military rulers "our disappointment that these several citizens are not being allowed to depart Egypt," as Washington continued to try to resolve the issue.
US Defense Secretary Leon Panetta telephoned Egypt's military ruler, Field Marshal Hussein Tantawi, at the weekend and asked him to lift the travel ban on US citizens working for US-funded NGOs, including the International Republican Institute (IRI).
Among them is the Egypt director of IRI, Sam LaHood, the son of US Secretary for Transportation Ray LaHood.
The ban has further strained US-Egyptian ties after Cairo prosecutors last month stormed the offices of the IRI, the National Democratic Institute and Freedom House as part of a probe into allegations of illegal foreign funding.
They were among 17 offices of local and international NGOs raided. The crackdown was part of a wider campaign by Egypt's military rulers to silence dissent after months of criticism of its human rights record, analysts said.
US Senator John McCain said he wrote to Egypt's leaders warning them that the controversy, if unsolved, could affect more than $1 billion in annual US military aid.
The State Department has already hinted that funds could be withheld under a bill enacted last month linking the aid to democratic progress, and the bill's sponsor, Senator Patrick Leahy, said Congress is ready to apply pressure.
"This (dispute) can affect our whole relationship, particularly our military aid," McCain said on CNN television.
"It's terribly disappointing. These organizations have been in many, many countries many times. They don't sway anybody's public opinion. They help them with the fundamentals of democracy," the Republican senator said.