Syria's official news agency SANA on Sunday denounced Turkey's prime minister for making a cross-border trip to a historic tomb inside Syrian territory, calling the visit a "clear aggression".
Prime Minister Ahmet Davutoglu made the surprise visit to the tomb of Suleyman Shah, grandfather of the Ottoman empire's founder Osman I.
The trip, which was not announced in advance, is the first such visit by a Turkish political leader to the tomb of Suleyman Shah, grandfather of the Ottoman empire's founder Osman I, just 200 metres (650 feet) from the Turkish border inside Syrian territory in the settlement of Eshme.
"Davutoglu's infiltration into Syrian territory without the permission of the Syrian government constitutes a clear aggression against a sovereign UN member state and a violation of international law," SANA said.
The tomb of Suleyman Shah, said to have died in 1236, is considered Turkish territory under the 1921 Treaty of Ankara between Turkey and France, which then controlled French-mandated Syria.
In February, hundreds of Turkish soldiers staged an unprecedented incursion deep inside Syrian territory to move the tomb from its previous location.
The tomb complex, which is considered sovereign Turkish territory, had been located some 37 kilometers (23 miles) inside Syrian territory.
But the government ordered the tomb, which has a permanent honor guard of Turkish troops, to be moved due to security concerns as it was located in territory controlled by Islamic State (ISIS) jihadists.
Army chief of staff Necdet Ozel, flanked by commanders from land and air forces, visited the tomb in March.
It was relocated from its previous site in February, in an unprecedented operation in which Turkish soldiers penetrated deep into Syria, also sparking a protest from Damascus.
Images of Davutoglu's visit showed him paying his respects and embracing Turkish soldiers stationed there.
SANA said the visit came in the "framework of election campaign propaganda" by Turkey's ruling Justice and Development Party (AKP), which it said was facing "a significant decline in popularity" ahead of a June 7 parliamentary election.
Turkey has been a key backer of the uprising against Syria's government, which accuses Ankara of supporting "terrorists".
The visit comes amid speculation Turkey was preparing to intervene militarily in Syria, a claim rejected by Davutoglu.
Some politicians in the opposition Republican People's Party (CHP) claimed this week that the ruling Justice and Development Party (AKP) might resort to military operations in Syria to boost its popularity ahead of a June 7 parliamentary election.
"No, there is no situation right now that requires Turkey's involvement," Davutoglu told Turkish media this weekend, labeling the claims as "empty words".
Davutoglu was due to continue his election rally on Sunday in the city of Sanliurfa in the southeast near the Syrian border.
AFP contributed to this report.