By Ercan Gurses and Tuvan Gumrukcu

ANKARA (Reuters) - Turkish Prime Minister Ahmet Davutoglu briefly crossed into Syria on Sunday to visit the tomb of a revered Ottoman figure and vowed Turkey's flag would fly there forever, prompting Damascus to accuse him of aggression.

The tomb of Suleyman Shah, grandfather of the founder of the Ottoman Empire, had originally been situated further inside Syria but was relocated to within a few hundred meters of the border in February in a Turkish military operation.

Davutoglu made the brief foray over the border shortly before addressing campaign rallies for a June general election in the southern cities of Sanliurfa and Adana.

"I bring you the salutations of Suleyman Shah, the leader of our revival," he told the Sanliurfa rally. "Our red flag will fly over Suleyman Shah forever."

The Syrian government condemned what it described as Davutoglu's "infiltration" without its permission.

"(It) is a clear aggression on a country with sovereignty and a breach of laws and international accords," said a government statement released on the state news agency SANA.

The relocation of the tomb, which involved tanks, drones and reconnaissance planes as well as several hundred ground troops, was the first incursion by Turkish troops into Syria since the start of the civil war there four years ago.

No clashes took place during that operation, although one soldier was killed in an accident.

Turkey, a NATO member with a 900-km (560-mile) border with Syria, wants President Bashar al-Assad removed from power but has refused to take a frontline military role in a U.S.-led coalition, arguing that fighting Assad's forces, not just bombing Islamic State militants, should be the aim.

The tomb had been on a site within Syria that Ankara considers sovereign territory as agreed in a 1921 treaty. The Turkish government informed the Syrian consulate in Istanbul about the February operation but did not await Syria's agreement, which Damascus said violated the treaty.

(Reporting by Suleiman al-Khalidi in Amman; Writing by Nick Tattersall; Editing by Tom Heneghan)