Secretary of State John kerry arrived in Egypt Sunday on a surprise trip, becoming the highest-ranking US official to visit since President Abdel Fattah al-Sisi came to power.
kerry was to meet Sisi during his lightning trip to press the former army chief, who ousted Egypt's first democratically elected president, to install greater political freedoms and discuss security challenges.
Since Islamist president Mohamed Morsi was toppled in July 2013, a government crackdown on his supporters has left more than 1,400 people dead in street clashes and at least 15,000 jailed.
US officials warned Washington still has deep concerns about the government's "polarising tactics," even though there was a "recognition that Egypt has been going through a very difficult transition".
kerry's visit comes a day after an Egyptian court confirmed death sentences for more than 180 Islamists, including Muslim Brotherhood chief Mohamed Badie, after a speedy mass trial that sparked an international outcry.
The US officials also revealed that a tranche of about $572 million (420 million euros) in aid, which had been frozen since October, was released to the Egyptian government about 10 days ago after finally winning a green light from Congress. It will mainly go to pay existing defence contracts.
US officials announced in April they planned to resume some of the annual $1.5 billion in mostly military aid to Cairo including 10 Apache helicopters for counterterrorism efforts in the Sinai peninsula.
But the aircraft remain in storage in the US, an official confirmed Sunday.
Sisi won some 97 percent of the vote in May elections nearly a year after the military toppled Morsi, and installed an interim government.
Last week a new Egyptian cabinet led by Prime Minister Ibrahim Mahlab was sworn in with most of the ministers from the previous interim government still in place.
- 'Longstanding relationship' -
kerry will also meet with the new foreign minister, Sameh Shoukri, a former ambassador to Washington, during his trip which will only last a few hours before he heads to Amman.
"There's a strong desire on the part of the United States for this transition to succeed," a senior State Department official told reporters travelling with kerry.
"We have a longstanding relationship ... that's built on several different pillars. It's at a difficult juncture right now, that's true, and we have serious concerns about the political environment," the official said.
Egypt, one of only two Arab nations to have a peace treaty with Israel, has long been seen as a key strategic ally and a cornerstone to regional stability.
But the political turmoil since the 2011 uprising that toppled strongman Hosni Mubarak has paralysed Egypt, leaving it more concerned with domestic problems than regional matters despite the upheavals of the Arab Spring.
Washington has repeatedly called on Sisi and the military leaders to put the country back on the road to democracy and fulfil the promise of its revolution.
Concerns included a new law controlling demonstrations, "the lack of space for dissent, mass trials and death sentences," the official said.
"We are concerned that some of the tactics they're using to address their security issues are polarising ... they in some ways radicalise certain aspects of Egyptian society in ways that are not supportive of overall stability."
In a sign of Washington's unease over the path being taken by Egyptian leaders, no top US cabinet members attended Sisi's inauguration earlier this month.
kerry will insist in his meetings that the US still needs to see a return to the rule of law if US-Egypt ties are to improve.
"Because it's a complicated relationship and we are balancing different interests... we felt like this was an appropriate time ... for the secretary to come here to explore those shared interests," the US official said.