Israel on Monday fired a warning missile on Syria since the 1973 Yom Kippur War, breaking a long standing ceasefire and drawing itself into the ongoing bloody fight between President Bashar Assad's regime forces and the rebels in the strife-torn country.
Israel defence forces said they fired the missile as a warning shot on Sunday after a stray mortar from Syria hit a military post in the Golan Heights.
The errant shell marked the fourth time in just over a week that the infighting from Syria has spilled into Israel.
"IDF forces fired warning shots and relayed a message to the Syrian forces via the United Nations that warns against additional fire. Additional fire will prompt a quick response," a statement from the Israeli army said.
No injuries or damage were reported.
Following the threat of escalation, United Nations chief Ban Ki Moon appealed to Israel and Syria to ease tensions on their disputed Golan Heights frontier.
"The secretary general is deeply concerned by the potential for escalation," said UN spokesman Martin Nesirky.
Syria and Israel must halt "firing of any kind" across the ceasefire line, said the UN
The missile fired by the IDF was an advanced Tammuz missile, an electro-optic missile that is based on Spike long-range missile technology developed by Rafael Advanced Defence Systems.
IDF sources said that it was likely that the mortar attack on Golan Heights was the result of the ongoing clashes between the Syrian army and rebel forces, and that "Israel was not intentionally targeted".
IDF spokesman Brigadier-General Yoav Mordechai said that the army's decision to retaliate, which was authorised by Chief of Staff Benny Gantz, had taken into account the fact that during the last two months, eight such events were recorded, including mortar and light-artillery fire as well as Monday's mortar hit.
"We also notified the UN of the incident and repeated the warning given to Syria, that the IDF will not tolerate any fire on Israel. We will be monitoring the situation to see if the message was received," Mordechai said.
The Israeli army filed a written complaint with UN forces, which also has an Indian contingent, which is enforcing the ceasefire in Golan Heights.