Israel did not provide advance warning to the United States on its alleged Israeli airstrikes on Syria, a U.S. intelligence official said.
The unnamed official said the United States was told of the attacks as they were in progress, Reuters reported Monday.
The Israel Defense Forces has neither confirmed nor denied responsibility for attacks Friday and Sunday on what has been reported to be a shipment of long-range missiles from Iran en route to Hezbollah in Lebanon.
White House spokesman Josh Earnest told reporters Sunday afternoon that President Obama believes "the Israelis are justifiably concerned about the threat posed by Hezbollah obtaining advanced weapons systems, including some long-range missiles." Earnest added that the U.S. "is in very close contact" with the Israeli government.
Syrian state media accused Israel of an early Sunday morning attack on what it identified as the Jamraya military research center located approximately 10 miles from the border with Lebanon.
The New York Times reported late Sunday, citing rebels and local residents, that the strike on the research center killed more than 100 Syrian soldiers, many of them members of the country's elite Republican Guard, along with hitting the long-range missiles.
Reuters cited an unnamed "Western intelligence source" who confirmed the attack and said Israel targeted stores of long-range Fateh-110 missiles. The missiles have the capacity to strike Tel Aviv from Lebanon.