Israel has launched warning artillery fire into Syria after mortar shell hit military post in Golan.

In response, the military said in a statement that Israeli soldiers "fired warning shots towards Syrian areas." But according to the army source, the Israel Defense Forces (IDF) also launched artillery fire into Syria.

The Israeli army said there were no reports of damage or injuries in Sunday's incident and the IDF filed a complaint through the UN forces operating in the area.

This is the first time the IDF fired into the Syrian territory since 1973.

Meanwhile, the spokesperson of the IDF said the Syrian army should be responsible for the incident, according to local radio.

Israeli defense officials believe both Sunday and last Tuesday' s mortar shells were related to the inner-fighting in Syria, Israel Radio reported.

In Tuesday's event, one of the shells landed on the fence surrounding the Alonei Habashan community near the demilitarized zone (DMZ) in the Golan Heights on the Israel-Syrian border, but did not explode. The other two exploded in open areas. No casualties were reported.

UN forces across the border have increased patrols along the Syria-Israel border to prevent any friction between the two countries.

"There have been sporadic firefights between the Syrian security forces, including the Syrian army, and armed members of the opposition in the area of separation in Golan," Martin Nesirky, spokesperson for UN Secretary-General Ban Ki-moon, said Tuesday.

He said that the activity "has the potential to escalate tensions between Israel and Syria, and jeopardizes the ceasefire between the two countries and the stability of the region."

Israel captured the Golan Heights from Syria in the 1967 Mideast war and annexed it later, an act not recognized by the international community. The DMZ was created after the 1973 war in which Syria tried to retake the strategic plateau, and Syria has long called for Israel's full withdrawal from the area and set it as a condition for making peace with Israel.