Both the White House and State Department congratulated the Lebanese people for carrying out a peaceful election.
A senior official who spoke here on terms of anonymity went further, welcoming what he said was an "unambiguous" victory by the March 14 movement and expressing hope that Hezbollah will accept the results and operate within the political system.
Despite pre-election forecasts that the Hezbollah-led opposition might gain seats, the pro-Western March 14 coalition won 71 of the 128 seats in parliament -- picking up one seat -- while the Syrian- and Iranian-backed opposition alliance led by Hezbollah won 57.
In a written statement, President Barack Obama said the Lebanese people had once more demonstrated to the world their courage and the strength of their commitment to democracy.
State Department Spokesman Ian Kelly called the election a critical step toward Lebanon's rightful achievement of true independence and sovereignty, and said the United States will continue to support a sovereign and independent Lebanon.
"With the voting over, the process of forming a government a developing a government program now begins. That is a process for the Lebanese to carry out in accordance with the election results and without outside interference," he said. "We look forward to working with the next government and hope it will continue along the path toward building a sovereign and stable Lebanon that is committed to peace, including full implementation of all United Nations resolutions," Kelly added.
March 14 coalition leader Saad al-Hariri has said he will invite Hezbollah to form a national unity government, but that he will not give the group enough cabinet posts to give it the veto power it holds in the current government.
The senior State Department official here said Hezbollah had made excessive use of its blocking minority since 2005 to hamstring the government, even on relatively mundane domestic issues.
He said Hezbollah now faces a different reality, with voters having handed the governing coalition a clear majority, although not a landslide victory.
He said the outcome was an affirmation that most Lebanese want to see the state in control of all the country's territory and that it undermines Hezbollah's argument that it should be both a political party and an Iranian-armed militia.
The United States has long listed Hezbollah as a terrorist organization for its role in 1980's attacks on U.S. troops and facilities in Lebanon, and other violent acts.
The senior official said the United States would be "happy" to reconsider its position on Hezbollah -- if it were to lay aside its weapons and become "just a normal political party" in Lebanon.