Syria is accusing Israel of raising tensions in the region by claiming that Damascus is supplying long-range missiles to Hezbollah militants in Lebanon.
Syria's Foreign Ministry denied the Israeli allegations Thursday. It said they appear to be aimed at giving Israel a pretext to attack Syria and avoid making concessions for peace.
Israeli President Shimon Peres accused Damascus Wednesday of talking about peace while delivering Scud missiles to Hezbollah with the goal of threatening Israel.
U.S. officials did not confirm that Hezbollah possesses Scuds. But, they said Washington is increasingly concerned about what they called the transfer of more sophisticated weaponry to Hezbollah.
The U.S. officials also said such transfers have a potentially destabilizing effect on the region and put Lebanon at "significant risk."
White House spokesman Robert Gibbs said Wednesday the Obama administration has communicated its concerns to the Syrian government.
Israel and Hezbollah fought a month-long war in 2006 that killed at least 1,200 Lebanese and about 160 Israelis. During the war, Hezbollah fired thousands of short-range Katyusha rockets into Israel, while Israeli forces carried out air and ground attacks on Lebanese territory.
The Obama administration has reached out to Syria in the past year by nominating a diplomat to be first U.S. ambassador in Damascus since 2005. It also has sent senior officials to meet with the Syrian president.
Washington withdrew its last ambassador to Syria after the assassination of former Lebanese Prime Minister Rafik Hariri in 2005. Many countries have blamed Syria for the assassination, but Damascus denies any involvement.
Some information for this report was provided by AP, AFP and Reuters.