Shelling hit two natural gas plants in the Syrian city of Homs, one day after Turkey struck targets in northern Syria. Syrian state TV reported early on Tuesday that shelling hit a gas plant in the south-central area of the city and the Ebla plant. Firefighters are still trying to put out a fire at the south-central area gas plant while no damage was reported at the Ebla plant. It was not immediately known whether production from the south-central area gas plant was affected and no further information was available on the source of the shelling. The Ebla gas plant provides local power plants with approximately 2.5 million cubic metres of gas per day and both plants are used to provide fuel domestically. No one has claimed responsibility for the shelling but Homs' location in central Syria means that rebels will probably be suspected of carrying out the attacks. Turkey hit targets in northern Syria in retaliation after shelling by regime forces killed seven Turkish soldiers and a civilian working for the military, Turkish President Recep Tayyip Erdogan said Monday. A Syrian war monitor said 13 Syrian troops were also killed. Syrian activists said air strikes in the country's northern Idlib province also killed at least nine civilians on Monday. The exchange of fire between Ankara and Damascus came hours after a large Turkish military convoy entered Idlib, the last rebel stronghold in Syria. The fighting is likely to further increase tensions between the two neighbours, as such direct clashes have been rare. It could also lead to friction between Russia and Turkey, which have sought to co-ordinate their actions in Syria. Earlier, Turkey's National Defence Ministry said the Turkish forces were sent to Idlib as reinforcements and attacked, despite having given their co-ordinates to local authorities beforehand. It said Turkish forces responded to the attack, destroying targets.