"If there is any US pressure on Egypt, it might possibly turn the situation from a separation of state and religion into a religious state," Surur, a senior member of the ruling National Democratic Party (NDP), told AFP.
Washington is growing increasingly critical of its ally after the arrests of more than 1,000 Islamist opposition supporters in the run-up to Sunday's parliamentary poll, and has unsuccessfully pushed Egypt to allow international monitors to observe the vote.
The Muslim Brotherhood, the largest opposition group, runs its candidates as independents to circumvent a ban on religious parties.
At least 1,200 of its supporters have been arrested since October, and it is expected to win fewer seats than the one-fifth of parliament it captured in the last election five years ago.
Surur said he made similar comments to a group of visiting US foreign policy experts earlier this month.
One of them, Robert Satloff, is a member of the Working Group on Egypt, comprised of foreign policy experts who have consulted with President Barack Obama's administration on Egyptian political reforms.
Satloff told AFP after meeting Surur that Washington, which had initially distanced itself from the robust democracy advocacy of Obama's predecessor George W Bush, wanted to ensure that Egypt's government had legitimacy.
"The US has an interest that the political process is open and transparent. We are eager for the Egyptian government to be as legitimate as possible," he said.
Analysts say Cairo, one of the top beneficiaries of US foreign aid, has used the threat of Islamists sweeping to power to ward off pressure to lift political restrictions in the NDP-dominated country.
Michele Dunne, a former State Department diplomat who is also a member of the Working Group on Egypt, says US officials are increasingly inclined to view the scenario of Islamists sweeping to power in Egypt as a hollow threat.
"It has come up in meetings when Mubarak meets with members of Congress," said Dunne, who is also a Middle East expert with the Carnegie Endowment for International Peace.
"The idea of of the Brotherhood sweeping to power is a straw man and people in the Obama administration see that," she said.
The Brotherhood won most of the seats it contested in 2005, but analysts say that result was partly due to protest votes against the NDP, which has dominated parliament for more than three decades.