The United States was "extremely concerned" about the clash Tuesday between the Israeli and Lebanese militaries and urged both sides to exercise restraint along the border, dpa reported.
Israeli and Lebanese troops exchanged fire along the tense border, leaving three soldiers dead - two Lebanese and one Israel. A Lebanese journalists also died in the firefight. A cease-fire was later declared.
"The United States is extremely concerned about the violence today along the Israel-Lebanon border zone," US State Department spokesman PJ Crowley said.
"We deeply regret the loss of life," he added. "We urge both sides to exercise maximum restraint to avoid an escalation and maintain the cease-fire that is now in place."
Crowley said the United States backs an investigation into the incident. The gunfire was the most serious clash along the border since Israel and Hezbollah guerillas fought a bitter war in 2006.