Hezbollah, a Lebanese Shiite movement, is backed by Iran.

The United States voiced concern Sunday after Israel and Hezbollah exchanged fire along the Lebanese border, slamming the "destabilizing role" of Iranian proxies in the Middle East.

"We are aware of these reports and are concerned about the escalating tensions along the border," said a State Department official.

"The United States fully supports Israel's right to self defense," the official said, warning that "Hezbollah should refrain from hostile actions which threaten Lebanon's security, stability and sovereignty."

"This is another example of the destabilizing role of Iranian proxies in undermining peace and security in the region," the official said.

Hezbollah, a Lebanese Shiite movement, is backed by Iran.