BEIRUT, Lebanon -- Secretary of State Condoleezza Rice yesterday made a surprise visit to this city to bolster the first government formed after Syrian forces departed in the spring, warning Syria to quit interfering in Lebanese politics and demanding that it end a border tightening that threatens to hurt Lebanon's fragile economy.

"Good neighbors don't close their borders to their neighbors," Rice said at a news conference with incoming Lebanese Prime Minister Fouad Siniora. "It is a very serious situation on the Lebanon border, where Lebanese trade is being strangled."

Shortly after Rice completed her seven-hour visit under tight security, an explosion rocked a busy street of restaurants and bars in a Christian neighborhood of Beirut late yesterday, Lebanese television stations reported.

The blast, which wounded two people, took place about 600 yards from one of the spots that Rice had visited earlier.

Rice said she made the unexpected trip to support what she called "the new Lebanon," one that she said would be democratic, "free of foreign influence" and where "Lebanese should make decisions for the Lebanese."

The secretary reiterated that the United States has no intention of dealing with representatives of Hezbollah, the pro-Syrian, Shiite Muslim movement that has gained 14 seats in the parliament and one Cabinet ministry

But she indicated that the United States for now would give the nascent government breathing room on how to deal with an organization Washington has labeled a terrorist group.

Rice said Hezbollah had a "history of blood," but "there is a process of political reconciliation that is under way in Lebanon," which it is important for the United States to support now.