Syria responded angrily to the overnight air strikes on military targets that it accused Israel of carrying out, warning that the attack "opens the door to all possibilities."
Israel has not claimed responsibility, but moved anti-missile batteries to the north and shut down the air space to civilian flights as tensions rise.
"We will not accept to be humiliated," Syrian information minister Omran al-Zoubi said at an afternoon press conference. "We are all in a state of anger. We are abused by this attack."
Israel hasn't confirmed or denied the series of strikes early today morning, believed to be the second set of strikes in 48 hours. On Friday, Israel hit what unidentified officials told The Associated Press was a shipment of ground-to-ground missiles bound for the Lebanese militant group Hezbollah.
Israel has long said that it would not hesitate to intervene to prevent advanced weaponry -- including chemical weapons -- from falling into the hands of its enemies.
Syria said Israeli warplanes hit three military targets today around Damascus, including an airport and the same Jamraya research center accused of developing chemical weapons that Israel attacked in January.
Syria accused Israel of "coordination" with the extremist rebel groups it is fighting, including Jabhat al-Nusra, which has pledged allegiance to al Qaeda's leadership.
The chief of staff of the armed forces in Iran -- which is allied with Syria and Hezbollah -- warned that "[Hezbollah] forces will respond to the Israeli aggression. ... Iran will not allow Israel to destabilize the region."
In the wake of the strikes, Israel moved two of its much-lauded Iron Dome anti-missile batteries to the north of the country to cover the Lebanese and Syrian borders, while shutting down the air space to commercial travel.
"There is a feeling of tension when we hear about what is happening in the area," the mayor of the northern town of Kiryat Shmona, Mayor Rabbi Nissim Malka, told the Haaretz newspaper. "Residents are calling the municipal hotline and asking questions like 'are the shelters open?' or 'are classes being held as usual?' We are calming everyone who calls and continuing daily routines."
Israel appeared to try to tamp down fears of imminent retaliation as Prime Minister Benjamin Netanyahu's office said he would continue with a trip to China tonight, though his departure was delayed as he convened his security cabinet.
Syrian state media said the Syria cabinet convened an emergency session to "discuss the Israeli aggression."
The Arab League, which largely backs the rebels in the Syrian conflict, blamed the strikes on Israel and called them a "dangerous violation of an Arab state's sovereignty."
President Barack Obama, who has faced growing questioning over the American role in the conflict that has left more than 70,000 dead, did not confirm the Israeli attacks but said Israel has a right to stop its enemies from getting advanced weapons.
He added that he does not foresee a time in which American troops will be sent into Syria.
"What I do know is that I cannot see a scenario right now in which American boots on the ground would make any sense," he told Spanish-speaking network Telemundo. "And I cannot see a scenario in which, actually, the Syrian people would benefit from American boots on the ground."