The call, which also dwelt on the danger of violence spilling over into Lebanon, took place after the Syrian government's assault on the rebel stronghold of Qusayr, which involved forces from Hezbollah.
"President Obama stressed his concern about Hezbollah's active and growing role in Syria, fighting on behalf of the Assad regime, which is counter to the Lebanese government's policies," said a White House statement.
"President Obama expressed his appreciation to President Sleiman and the Lebanese people for keeping Lebanon's borders open and hosting refugees from Syria, and pledged continued US support to help Lebanon manage this challenge.
In a battle beginning yesterday, Syrian government troops backed by Lebanese Hezbollah fighters stormed Qusayr, a strategically important location because it sits between Damascus and the coast and is near the Lebanese border.
Earlier, State Department spokesman Patrick Ventrell condemned "Hezbollah's direct intervention and assault on Qusayr where its fighters are playing a significant role in the regime's offensive."
"Hezbollah's occupation of villages along the Lebanese-Syrian border and its support for the regime and pro-Assad militias exacerbate and inflame regional sectarian tensions and perpetuate the regime's campaign of terror.
