Assistant Secretary of State for Near East Affairs Jeffrey Feltman said Wednesday giving such weapons to Hezbollah would be "an incendiary, provocative action." He would not confirm reports that Syria has sent Scud missiles to Hezbollah, but he said the administration viewed the matter with the gravest concern.
The US will be keeping "all options on the table" to press Damascus to "reverse course," he said.
Feltman told a congressional committee that Syria's leaders need to understand the risks of arming Hezbollah, which he said "could affect war and peace in the region."
Harsh Israeli warnings
Earlier, Israeli officials have warned of the grave consequences of Scud missile transfers to Hezbollah.
"We will return Syria back to the Stone Age," an Israeli minister was quoted as saying in British paper, the Sunday Times.
The paper reported that this sentiment was communicated to Damascus via a third party.
According to the report, the minister, speaking off the record, warned last week that Israel will carry out its threat against Syria by "crippling its power stations, ports, fuel storage and every bit of strategic infrastructure if Hezbollah dare to launch ballistic missiles against us."
Ynet contributed to the story