Recently, he has met with American officials like Senator John Kerry, Democrat of Massachusetts, and Ambassador Anne W. Patterson, and he is soon to meet with Deputy Secretary of State William J. Burns. Mr. Erian brushed aside recent reports by some Arab news outlets that the Brotherhood planned to reject American aid to Egypt, including the military aid of about $1.3 billion a year that Egypt has received since it signed the Camp David accord with Israel in 1978.

“If the Americans are ready to support a democratic government in Egypt, this means a lot,” Mr. Erian said, adding that he hoped the United States would “continue the aid, but without political pressure.”

The Brotherhood, he said, would honor the Camp David accord. “This is a commitment of the state, not a group or a party, and this we respect,” he said.

But Mr. Erian also said that it was now time for Israel to understand the implications of the democratic openings of the Arab Spring — “the biggest change in the Arab world’s history” — which have given new voice to Arab anger at Israel’s occupation of the Palestinian territories.

And he reminded his American visitors that they were not the only ones to come calling. “Everyone wants to see us,” he said. “The Chinese were here, the Russians were here.”

Mr. Erian acknowledged that the Brotherhood was surprised by the electoral strength shown by the ultraconservative Islamists known as Salafis, whose Al Nour party has received about 25 percent of the vote so far. Salafi leaders have espoused a variety of radical proposals about applying Saudi Arabia-style Islamic law in Egypt as soon as possible — cutting off the hands of thieves, stoning adulterers, banning alcohol, imposing conservative standards of decency on women’s dress, and censoring arts and entertainment.

“It is clear that they are a political power,” Mr. Erian said.

Still, he dismissed the fears of many Western observers, including some in Washington, that the need to compete with the Salafis would pull the Brotherhood to the right. “We hope that we can pull the Salafis toward us, and both of us will be pulled by the people’s needs,” Mr. Erian said.