Israeli airstrikes against Syrian military positions in the Golan Heights killed one soldier and wounded seven in the most serious escalation between the two neighbors since Syria's civil war broke out three years ago.
Syria's military confirmed the casualties from the strikes, which came in response to an attack Tuesday on Israeli forces across the Israeli-Syrian cease-fire line in the Golan.
Both sides issued stark warnings following the incidents.
Israeli military officials said the targets Wednesday included an army training facility, military headquarters and artillery batteries that had "aided and abetted" the earlier attack on an Israeli army patrol.
The bomb attack was the third such incident along Israel's northern borders in less than two weeks and the first to cause Israeli casualties. Four soldiers were wounded, one severely.
An Israeli military spokesman called the blast "an unacceptable escalation of violence from Syria" and vowed that Israel would not tolerate threats to its forces and people.
The attacks appear to have been carried out in revenge for a series of airstrikes blamed on Israeli forces over the past year against weapons convoys and warehouses, mostly in Syrian territory.
Israeli says it will act to prevent the transfer of advanced weapons from Syria to the Lebanese Shi'ite Hezbollah militia, which is currently fighting in Syria to aid that government's fight against Sunni rebel forces.
Also Wednesday, Syria and its Russian ally criticized the decision by the United States to suspend the operations of Syria's embassy in Washington and consulates in other cities.
The Syrian Foreign Ministry condemned the action as a violation of international diplomatic conventions, while Moscow called it "worrying and disappointing."
Syria announced on March 10 it would stop providing consular services in the United States. State Department officials said while embassy and consular activities were affected the U.S. was not severing diplomatic relations with Syria.
Meanwhile, aid officials said a U.N. convoy of about 80 trucks prepared to cross the Turkish border into Syria for the first time, a step they hope will pave the way for humanitarian access to the country's most desperate areas.
The U.N. Security Council last month unanimously called for Syrian authorities and rebels to allow prompt access for humanitarian supplies across front lines and borders by the most direct routes.
Last week, Syria granted its approval to the opening of the border crossing and sources said Turkey has also given the delivery the go-ahead.