The US State Department's number two was to sit down Wednesday with Muslim Brotherhood party leaders, as Egypt prepared to wrap up marathon elections that propelled Islamists to the centre stage of politics.
Washington has been reaching out to the Brotherhood in a nod to Egypt's new political reality, with Islamists poised to dominate the first parliament since a popular uprising ousted veteran president Hosni Mubarak in February.
US Deputy Secretary of State William Burns "will meet leaders of the (Brotherhood's) Freedom and Justice Party at their headquarters in Cairo," FJP spokesman Ahmed Sobea told AFP.
"It will be the highest-level meeting with any official from the United States," Sobea said.
Burns, who arrived in Cairo late on Tuesday, met with Field Marshal Hussein Tantawi, head of the Supreme Council of the Armed Forces (SCAF) which took power when Mubarak was ousted.
He is also expected to meet other government officials, political and business leaders as well as activists.
Secretary of State Hillary Clinton said before the polls that the United States had pursued "limited contacts" with the Brotherhood as Washington was "re-engaging in" a six-year-old policy in light of Egypt's political changes.
FJP deputy head Essam Al Erian held talks with Jeffrey Feltman, US assistant secretary of state for Near Eastern affairs, during a recent visit to Cairo, Sobea said.
Wednesday's meeting comes as Egyptians voted in the final phase of staggered polls to elect a lower house of parliament.
Egypt's two main Islamist parties have scored a crushing victory in the seats declared so far, reflecting a regional trend since Arab Spring uprisings overthrew authoritarian secular regimes.
The FJP has claimed the lead -- securing over 35 percent of votes for party lists -- closely followed by Al Nur party, which represents the ultra conservative brand of Salafi Islam.
Burns was not expected to meet with representatives of Al Nur, a spokesman for the party told AFP.
The powerful Muslim Brotherhood, the country's best organised political movement was widely expected to triumph in the polls through its party, the FJP.
But the surge of Al Nur and the strong visibility of Salafi movements have raised fears among increasingly marginalised liberals about civil liberties and religious freedom.
The SCAF has repeatedly pointed to the elections as proof of its intention to hand the reins to a civilian government.
But the vote has exposed a deepening rift among Egyptians. Some see them as the first step to democratic rule, while others say the new parliament -- whose function remains unclear -- leaves control in the hands of the military.
The SCAF has faced growing outrage over the actions of security forces against demonstrators for an immediate transition to civilian rule, which have resulted in dozens of deaths and been widely criticised as heavy-handed.
Burns was also expected to discuss a major US dispute with Egypt over Cairo's crackdown on non-governmental organisations (NGOs), including US election monitoring groups.
Late last month, Egyptian prosecutors backed by police special forces stormed 17 offices of local and international NGOs, confiscating computers and documents as part of a probe into allegations of illegal funding from abroad.
The most populous Arab country, Egypt has been the lynchpin of US policy in the Middle East since 1979 when it became the first Arab state to sign a peace treaty with Israel.
Egypt receives $1.5 billion in annual US military.