"Pakistan is an important partner and ally to the United States and we congratulate them for today's election," White House spokesman Scott Stanzel said, refusing to comment on the winner until an official declaration is made.
"We look forward to the electoral commission's announcement and to working with all of Pakistan's leaders on important bilateral, regional and counter terrorism issues," he said.
Musharraf, a key US ally who seized power in the nuclear-armed Islamic republic in a 1999 coup, crushed token rivals in a vote by national and provincial assemblies that was mostly boycotted by the opposition.
But the embattled general must now await a decision by the Supreme Court, which said Friday that the winner cannot be officially declared until at least October 17 while it hears legal challenges.
The State Department gave a similarly cautious response to the chief election commissioner's report that Musharraf won 252 of 257 votes cast in the national assembly and senate.
"We are waiting for a declaration from the Pakistan Supreme Court. We will not have a comment until that declaration is made," a State Department spokeswoman said.