JERUSALEM - Israel fired a warning shot into Syria on Monday for a second day running after a mortar round hit the Israeli-occupied half of the Golan Heights, security sources said.
The exchange came just hours after an appeal for restraint from all sides by UN chief Ban Ki-moon.
An Israeli security source confirmed that troops had returned fire after a mortar round from Syria hit the central sector of the strategic plateau, causing no casualties or damage.
"Israeli troops fired a warning shot towards the source of fire," the source said, speaking on condition of anonymity.
Israeli troops fired a warning shot across the UN-monitored ceasefire line on Sunday in the first such shooting on the Golan since the 1973 Middle East war.
Sunday's mortar round, which hit an Israeli position, drew a warning from Defence Minister Ehud Barak that Israel would take "tougher" action in response to any new fire from Syria.
The Israeli military confirmed that another mortar round had hit on Monday but could not immediately confirm troops had returned fire.
"A mortar shell landed in the same approximate area as yesterday's fire, on open ground... in the central Golan Heights," a spokeswoman said.
"There were no casualties and no damage caused."
Ban's spokesman Martin Nesirky said after Sunday's fire that the UN chief was "deeply concerned by the potential for escalation".
"He calls for the utmost restraint" and urges both sides to uphold the 1974 accord which set up the ceasefire line and surrounding demilitarised zone.