BEIRUT, (AP) – For years, the U.S. has pumped money into Lebanon’s military, hoping a strengthened army would sideline Iranian-backed Hezbollah’s powerful militia.

The unexpected decision by a U.S. Congressman to suspend that aid over concerns the weapons could be turned on Israel again raises one of Lebanon’s most vexing questions: Who is really in charge of the Arab nation?

Hezbollah is undoubtedly the country’s most powerful military force, with an arsenal that far outweighs that of the Western-backed national army.

Lebanon’s government is an uneasy coalition of a Western-backed bloc, headed by Prime Minister Saad Hariri, and Hezbollah, which in just a few years has gained so much political power it now has a virtual veto over government decisions. Hariri’s bloc wants the Islamic militant group to disarm, but does not have the power to force its will.

The power balance has long worried the U.S. and its close ally Israel, which is Hezbollah’s sworn enemy.

“We continue to believe that supporting the Lebanese government and the Lebanese army or military is in our national interest,” U.S. State Department spokesman P.J. Crowley said Tuesday. “It contributes to stability in the region.”

On Monday, the chairman of the House Foreign Affairs Committee said he suspended U.S. military aid to the Lebanese Armed Forces on Aug. 2 amid growing concern in Congress that American-supplied weapons could threaten Israel and that Hezbollah may have influence over the army.

Rep. Howard Berman, a Democrat from California and a strong supporter of Israel, said those concerns were reinforced a day later when the armies of Lebanon and Israel fought along their border, killing two Lebanese soldiers, a Lebanese journalist and a senior Israeli officer.

“We will address the concerns that congressional leaders have rightfully raised about what happened recent and what it’s potential implications are,” Crowley said. “But nonetheless we continue to support our assistance programs to Lebanon.”

Hezbollah did not take part in the most recent fighting, and the confrontation showed a rare willingness by the Lebanese military to assert itself in a region long considered Hezbollah territory.

The Lebanese army drew praise in the country for standing up to Israel’s powerful military — a role the army has more or less deferred to Hezbollah in the past. But politicians in Israel and the United States charge that Hezbollah might have infiltrated the army or are trying to influence it.

It is a paradox that Lebanese military aid presents to the U.S. administration, which wants to a see a stronger army to counter Hezbollah’s formidable arsenal but now faces the possibility that the army may end up trading fire with Israeli soldiers.

“In essence, the U.S. administration and U.S. military aid to Lebanon are caught between an Israeli rock and a Hezbollah hard place,” said Aram Nerguizian, a resident scholar at the Center for Strategic and International Studies in Washington.

Nerguizian said that while the clash seems to be an isolated incident, it shows the army wants to play an increasingly meaningful role in safeguarding Lebanese sovereignty.

On the same day Congress announced its suspension in aid, the U.S. State Department spokesman defended U.S. assistance to Lebanon and said it contributes to “regional stability as a whole,” suggesting that the White House does not share fears that aid to the Lebanese army will be turned against Israel.

Crowley said he was not aware of plans to reevaluate U.S. military cooperation with Lebanon. It was not clear how long the suspension would last; Berman used his legislative prerogative to place a temporary hold.

The Aug. 3 clash — the most serious fighting since the 2006 Israel-Hezbollah war — began after an Israeli soldier tried to remove a tree along the border, something the military has done in the past to improve its sightlines into Lebanon.

But both sides claimed the tree was in their territory, and Lebanon said it opened fire after Israel refused entreaties to stop. The United Nations later determined the tree was on the Israeli side.

Lebanon described the U.S. suspension of aid as “regrettable and unwarranted.”

“The last thing that the U.S. or any other friend of Lebanon should do is to weaken the effort to build up our national army,” Mohamed Chatah, an adviser to Prime Minister Hariri, told The Associated Press.

Some analysts believe cutting U.S. aid could actually empower Hezbollah.

“It would facilitate Hezbollah reasserting itself along the line of demarcation with Israel,” Nerguizian said.

For years, Lebanon’s 60,000-strong military was dismissed as little more than an internal security force. It has stayed out of the frequent battles between Israeli forces and Hezbollah, including the 2006 war when Israeli airplanes pounded army positions while the military largely stayed on the sidelines.

Following the war, the army deployed in southern Lebanon — Hezbollah’s heartland — for the first time in decades, with the help of U.N. peacekeepers. Since then, the U.S. has stepped up its military assistance to the Lebanese army.

The United States has since 2006 provided over $720 million in military aid, including assault rifles, Humvee vehicles, missile and grenade launchers and night vision goggles, in addition to training.

Israeli Defense Minister Ehud Barak said his country always has had concerns that the army’s weapons could find themselves in the hands of Hezbollah.

“But in front of our eyes something even more disturbing is happening, it’s being used directly by the Lebanese army against us,” he alleged.