Two Turkish soldiers were killed by Syrian government forces in the northwestern region of Idlib, Turkey's defence ministry said Wednesday.
Six others were wounded in the shelling, it said, adding that Turkish forces "immediately" retaliated against regime targets.
The ministry also said late Tuesday on Twitter that one Turkish soldier was killed by Syrian fire and nine others had been injured.
More than 50 Turkish soldiers have been killed in the rebel-held region in recent weeks, including 34 who died in an air strike on Thursday.
Turkey officially declared an operation against the Russian-backed regime of Syrian President Bashar al-Assad over the weekend, named 'Spring Shield'.
It has since downed three Syrian warplanes, and killed dozens of regime soldiers and allied fighters -- mostly through drone strikes -- according to monitors.
Turkey, which backs certain rebel groups in Idlib, has sought to push back Syrian forces behind lines agreed under a 2018 deal with Russia, which established 12 Turkish observation posts in the province.
But Syrian forces, supported by Russian air power, has retaken swathes of territory since launching its offensive in December, killing hundreds of civilians and forcing nearly a million to flee their homes.
Despite being on opposite sides of the war, Ankara and Moscow have kept lines of negotiation open, and President Recep Tayyip Erdogan is due to meet his Russian counterpart Vladimir Putin in Moscow on Thursday in search of a new ceasefire.
Turkey, which already hosts some four million refugees, wants to prevent another influx from Idlib.
It has pressured Europe for greater assistance by announcing that migrants and refugees would no longer be prevented from trying to enter the EU via the Greek border.
The nine-year Syrian conflict has killed over 380,000 people and displaced millions since it began in 2011 with the brutal repression of anti-government protests.