WASHINGTON (Reuters) – The United States voiced  concern yesterday that Syria may have supplied Lebanese  Hezbollah guerrillas with Scud missiles that can hit deep  inside Israel, potentially altering the military balance  between the long-time foes.

A day after Israeli President Shimon Peres accused Syria of  handing over “sophisticated Scud missiles to Hezbollah that  threaten Israel,” the White House said it had warned Damascus  of a possible “destabilizing effect” for the region.

“There’s concern that this is under consideration, but it’s  unclear whether or not the missiles have been transferred,”  said a US official, speaking on condition of anonymity.

Such a development could threaten US President Barack  Obama’s diplomatic outreach to Syria and create new obstacles  to the confirmation of a new US ambassador to Damascus after  a five-year absence.

One Israeli official, speaking on condition of anonymity,  said the Scuds were smuggled in to Hezbollah, an Islamist group  backed by Iran and Syria, over the past two months.

Another Israeli official said the missiles were believed to  have come without launchers but called that “irrelevant” since  they were placed in improvised silos. There was no immediate  word on where in Lebanon the missiles were stationed.

The Obama administration said it made its displeasure known  at the highest levels of Syrian President Bashar al-Assad’s  government.

“We obviously are increasingly concerned about the  sophisticated weaponry that … is allegedly being  transferred,” said White House spokesman Robert Gibbs.

“We have expressed our concerns to those governments and  believe that steps should be taken to reduce any risk and any  danger of anything from happening,” he told reporters.

Hezbollah fought a war with Israel in 2006 that cost  Lebanon a heavy civilian toll. The group fired off barrages of  rockets with ranges of 20-60 miles (32-96 kms) that forced  evacuation of large parts of northern Israel.

The Scuds reported to have been sent to Hezbollah are  believed to have a range of more than 435 miles (700 kms),  which would put Jerusalem, Tel Aviv and Israel’s nuclear sites  within range, the Wall Street Journal reported, citing Israeli  and U.S. officials.

Threat to Lebanese

Washington said the presence of Scuds on Lebanese soil  could threaten the country’s stability.

“If such an action has been taken, and we continue to  analyze this issue … clearly it potentially puts Lebanon at  significant risk,” said US State Department spokesman PJ Crowley.