BEIRUT – A senior U.S. official denounced Hezbollah’s involvement in the Syrian civil war Monday and accused the Shiite militant group of putting the interests of Iran and Syria above those of the Lebanese people.

Underscoring growing sectarian bitterness, mainly Sunni rebels vowed to “liberate” two Shiite villages they’ve had under siege in northern Syria if residents don’t renounce President Bashar Assad’s regime and force out his troops and Hezbollah fighters.

The comments by Deputy Secretary of State William Burns were the first by a high-ranking visiting U.S. official since Hezbollah helped propel Assad’s troops to victory last month in the strategic town of Qusair near the Lebanese border.

Syrian troops have been building on the victory to move against rebel-held areas elsewhere in the central province of Homs and in the north. On Sunday, troops hammered rebel-held districts in Homs with artillery, tanks and warplanes, part of a government offensive launched Saturday morning.

Fighters from the powerful Iranian-backed group have joined Assad’s forces in their battle to crush the rebellion, which is dominated by Sunnis.

“Despite its membership in the Lebanese government, Hezbollah has decided to put its own interests and those of its foreign backers above those of the Lebanese people,” Burns told reporters Monday.

“That intervention may be in Hezbollah’s interests, it may be in the interest of Iran, it may be in the interest of Bashar Assad, but it is not in the interest of Lebanon or the Lebanese people,” Burns said.

He added that the U.S. condemned “in the strongest terms” Hezbollah’s actions in Syria and said they “place the future of Lebanon at risk.”

The U.S. considers Hezbollah a terrorist organization.