Spokesman Gordon Johndroe made the call on May 9 during a news briefing in Crawford, Texas.
"We are very troubled by the recent actions of Hizballah," Johndroe said. "We urge Hizballah to stop their attempt to defy the lawful decisions taken by the democratically elected Lebanese government. We also urge Iran and Syria to stop their support of Hizballah and its destabilizing effects on Lebanon."
As Saudi Arabia called for an urgent meeting of Arab foreign ministers to defuse the crisis, Johndroe urged the countries in the region to support Lebanon's "democratically elected government."
Johndroe also said the White House was conferring with the UN Security Council on possible action against those responsible for the violence.
In a separate statement, U.S. Secretary of State Condoleezza Rice said Washington was committed to helping Lebanese Prime Minister Fuad Siniora and to reaching out to world leaders for ways to support his government.
Civil War Next?
The fighting has stoked fears that Lebanon is heading for another civil war.
Cabinet minister Ahmad Fatfat accused Hizballah of stirring "dangerous" strife between Sunnis and Shi'as across the country.
And Lebanon's Western-backed governing coalition called Hizballah's actions an "armed coup" aimed at increasing Iran's influence and restoring that of Syria. The statement was read by Christian leader Samir Geagea.
"What happened in Beirut and in its airport was an armed coup done by Hizballah," Geagea said. "It was a coup against the constitution, against national accord, [and] against the international resolutions and especially the last one 1701 (prohibiting all armed militias from operating in Lebanon). And it aims to weaken the state and attack against freedom and democracy."
The latest fighting was sparked by a government decision on May 5 to shut down Hizballah's telecoms network.
On May 9, Hizballah militants and their allies overran several Sunni neighborhoods in western Beirut, considered strongholds of Lebanon's ruling bloc. The gunmen forced the closure of pro government media. The Lebanese military did not intervene.
The escalation of the Lebanese crisis comes amid Washington's increasing efforts to isolate Iran in the region. Syria is Iran's closest ally in the Mideast.
The Iranian press has quoted Foreign Ministry spokesman Mohammad-Ali Hosseini as saying Tehran was working to end the crisis in Lebanon and blamed the United States and Israel for the latest violence.
On May 10, Syrian President Bashar al-Assad said the political crisis there was an "internal matter." Syria withdrew its army from Lebanon in 2005.
Hizballah is widely considered to have been fully rearmed by Iran and Syria following the Shi'ite militia's war with Israel in 2006.