Senior US official vows to counter Iran on Lebanon visit A senior U.S. official says the U.S. will step up efforts to counter Iran's "dangerous activities" around the region including the financing and activities of proxy organizations such as Lebanon's Hezbollah

BEIRUT -- The U.S. will step up efforts to counter Iran's "dangerous activities" around the region including the financing and activities of proxy organizations such as Lebanon's Hezbollah, a senior U.S. official said Monday.

U.S. Undersecretary of State for Political Affairs David Hale spoke following talks he held with Lebanese politicians at the end of an official visit. It comes amid a domestic political crisis over an ongoing government vacuum and tensions along the southern border, with the discovery of what Israel says are cross-border tunnels dug by the Hezbollah group for attacks on Israel.

"It's unacceptable to have a militia outside the control of the state and unanswerable to all the people of Lebanon, digging attack tunnels across the Blue Line into Israel, or assembling an arsenal of over 100,000 missiles with which to threaten regional stability," Hale said after meeting with the Lebanese Prime Minister-designate, Saad Hariri.

He pledged continued support for the Lebanese military and security forces and said that while Lebanon has the right to defend itself, "that is the right of the Lebanese state alone."

Hale spoke a day after Israel said it concluded a weekslong operation that destroyed Hezbollah-dug tunnels stretching into Israel. Israel and the United Nations said the tunnels violate a cease-fire resolution that ended a devastating war between Israel and Hezbollah in 2006. Hezbollah has not commented on the subject.

Hale said the U.S. was concerned about the ongoing government vacuum in the country, which is threatening to scuttle $11 billion in international donors' funds.

"Crucial economic reforms languish while obstructionism drags down the economy endangering the country," he said. He added that the caretaker government should move forward where it can, especially on the economy, to avoid further damage and maintain international confidence.

Hale also reiterated that the U.S. will be bringing American troops home from Syria but says America remains committed to ensure that the Islamic State group is unable to remerge.

"Through diplomacy and cooperation with our partners, we will expel from Syria every last Iranian boot and work with the U.N.-led political process to bring peace and stability there," he said.